BoppreH
3 days ago
Worse yet, the Ubuntu security incident page[0] lists "Ubuntu Priority: High" (as opposed to Critical, which would trigger an out-of-schedule patch). There's a "Why this priority?" link that simply says:
> Why is this CVE high priority?
> See ubuntu cvss score
That's it, we don't even get a period on this TBD of a sentence. It's followed by a generic link that explains what "Ubuntu Priority" is, but that page contradicts their choice. Note that it doesn't offer any mitigations either, and even the (horrendously unclear) description is copied from the NIST page, so there's no actual message from Ubuntu.
I already had a bad feeling the first time I saw "Get more security updates through Ubuntu Pro" on `apt upgrade`, this is now the kick I needed to move to a different distro.
[0] https://ubuntu.com/security/CVE-2026-98432#priority-reason
WesternStar
3 days ago
I don't think this is fair. They don't do a good job of pointing you at their rationale which is in their security score here[0]. I ultimately had to have claude translate the kernelese in to something my small brain could understand but this is a bug that could crash your system but is unlikely to expose your confidential system data to attackers or degrade data on the system. Especially given that the exploit can only be done if packets with IP options. IP options are commonly dropped or removed from packets on the open web. You not only need a vulnerable system but a vulnerable request path through the internet which you would only know by trying this attack which is very timing dependent with the SYN,Retransmitted SYN and Reset all happening very close together. A motivated attacker could probably do this on your network but over the internet ... It sounds unlikely.
BoppreH
3 days ago
> this is a bug that could crash your system but is unlikely to expose your confidential system data to attackers or degrade data on the system
Red Hat disagrees[0][1]. They might be parroting Anthropic, and Anthropic might be exagerating the impact (likely!), but that's the current consensus about the vulnerability. If Ubuntu disagrees, they should have said something and not pasted "Cvss 3 Severity Score 9.8 · Critical" at the top of the page.
> A motivated attacker could probably do this on your network
I find that's still catastrophic given how centralized cloud environments are.
[0] https://access.redhat.com/security/cve/cve-2026-98432
[1] https://access.redhat.com/security/vulnerabilities/RHSB-2026...
WesternStar
3 days ago
> I find that's still catastrophic given how centralized cloud environments are.
It's not like every cloud environment is vulnerable. GCP drops these options for example.
> If Ubuntu disagrees, they should have said something and not pasted "Cvss 3 Severity Score 9.8 · Critical" at the top of the page.
Again I'm going not going to argue they did a good job at pointing at their rationale but it looks like 9.8 is from CVSS 3.0 and they did prioritization with 4.0 which is 8.3. They definitely should have put that up front.
BoppreH
3 days ago
That would still be an RCE in the default install under certain circumstances, and the security advisory has no legible description or mitigations for an issue that other vendors have patched two weeks ago.
I would be perfectly ok if they had either quietly patched it earlier (like Debian), or communicated their prioritization, or they inexplicably delayed it but provided a high quality advisory (like Red Hat).
I don't like complaining about my fellow security engineers, but this one was real bad and is still personally affecting me.
ajross
3 days ago
> If Ubuntu disagrees, they should have said something
Exactly. There's room for considered differences of opinion, but that consideration requires discorse and explanation! The lack of communication here is just absolutely baffling. It's like they're deliberately trying to trash their own brand.
I mean, seriously what's going on? We know they have a process for emergency kernel updates, because of course they do. If they're not going to pull the trigger on this particular one (that everyone else is pulling the trigger on) at least make the case.
devy
3 days ago
Greg Kroah-Hartman the long-time Linux kernel maintainer (USB, PCI, driver core, sysfs, and -stable releases) gave a talk on LLM assisted CVE discoveries. In that talk, he downplayed those exposed CVEs from Mythos. What you described above matches his sentiment on downgrade those CVE vuln score.
See previous discussion and the actual talk on YouTube:
bawolff
3 days ago
> but this is a bug that could crash your system but is unlikely to expose your confidential system data to attackers
Given people have demonstrated getting root with it, unlikely seems questionable
> Especially given that the exploit can only be done if packets with IP options. IP options are commonly dropped or removed from packets on the open web.
It sounds like iphones use mptcp in the wild, which use tcp options, so im not sure how true this is.
wtch98
3 days ago
> It sounds like iphones use mptcp in the wild, which use tcp options, so im not sure how true this is.
There's so much commentary misunderstanding what ip-options are that I find it difficult to make any judgement call. I do know that I've got routers on 5 continents with hundreds of public IPs and none have triggered an IP packet with an ip-option arriving on the WAN side, or seen on the internal side other than ones I've created with scapy trying to reproduce this. I also can't get these packets to traverse any internet paths I've tried.
yusyusyus
3 days ago
TCP options are quite different from IP options.
IP options are annoying in big fast routers because they have to take the slow route via CPU. As there's not a lot of use in accepting packets (externally at least) with IP options, they tend to be dropped totally (but will almost certainly be policed aggressively to the CPU as the CPU is not good for moving many packets).
izacus
3 days ago
Who demonstrated getting root with it? The last I've seen was "trust me bro".
bawolff
3 days ago
Anthropic claims they have and they havn't been caught in a lie about this sort of thing yet. From a theoretical perspective, if a memory safety vulnerability in kernel network stack is exploitable, then root access would be the endgame so it fits.
izacus
2 days ago
So it's indeed "trust me bro!".
Tuna-Fish
2 days ago
What exactly do you expect them to do? Publish the exploit that can root a huge proportion of all linux servers?
Presumably they will publish it with sufficient fanfare once patches are applied widely enough.
tkinom
3 days ago
Asked claude/haiku5.5 to review that cve against my server, docker images. Claude had passwordless ssh access to that server and no root access. It did the review, confirm that server has the volubility, asked me to ran a few sudo commands, give it the output. It asked me to run a command to disable mptcp option.
I then asked it to do complete cve reviews on the host server (U 26.04 was installed a few weeks back) and docker images on that server and update the security review and added a task to do daily check on ubuntu website on kernel security update.
EDIT: Just asked claude if it can write a patch and build a image on top and fixed the issue on my server. It said it can. And point out that it can apply the 2 lines patches https://github.com/torvalds/linux/commit/e3f33b0.patch and build a kernel image on this issue for me. FYI....
throwaway382914
2 days ago
A problem, at least for me at work, is this has to be communicated to the people who make the decision around whether something can continue operating or has to be taken offline until fixed. So far, said people are not particularly interested in the details of CVEs, just if it's critical and has an exploit available. Which is fair I guess, they're absorbing the risk. I would like Canonical to go a bit faster which would make my life easier.
leni536
3 days ago
What about an untrusted local network, like public wifi?
voakbasda
3 days ago
Yeah, their lack of a satisfactory response is the final nail in their coffin. This incident escalates my consulting advice about Ubuntu from “not recommended” to “switch immediately”.
Some of my clients may be surprised by this change, as I once advocated for Ubuntu as a good choice for a development and deployment platform. While that has not been true for quite a while, they have now jumped the shark into eel-infested waters; I cannot take them seriously any longer.
InsidiousWombat
3 days ago
Plain Debian was always best option; even RHEL dropped the ball on this CVE and that's distro people pay for support
thayne
3 days ago
Not always. Notably, if you have compliance requirements like needing FIPS encryption (say because you have government customers), or that requires you to use a commercial vendor, debian won't work. And if you need more up to date system packages, or a reliable release cadence, Ubuntu might be better.
On desktop, if you need proprietary drivers, Ubuntu is easier to set up.
But yes, if debian works for you, I wouldn't use Ubuntu.
bityard
3 days ago
I had to deal with FIPS once because the company I worked for shipped a custom Linux distribution with the product and we had to essentially shoe-horn in some Red Hat OpenSSL packages to get it to meet FIPS requirements. What's funny is that after the customer enabled FIPS, administration became much harder, and the encryption strength was strictly worse.
Anyway, needing FIPS is something of a niche requirement. Debian or Rocky are very sane choices as a default Linux distribution for general-purpose servers until you run up against special requirements.
thayne
3 days ago
> Anyway, needing FIPS is something of a niche requirement.
For sure. Most of the time, Debian is just fine. But sometimes, if you have special requirements, something else might be better.
b112
3 days ago
Uh, yes it will. OpenSSL in Trixie is a version supported.
https://packages.debian.org/trixie/openssl-provider-fips
It's just the library, nothing special about the OS.
https://csrc.nist.gov/projects/cryptographic-module-validati...
As far as I know, compliance comes with an external module:
https://openssl-library.org/post/2025-03-11-fips-140-3/
This module seems to be in Debian:
# apt-cache search fips | grep open openssl-provider-fips - Secure Sockets Layer toolkit - cryptographic utility
# dpkg -L openssl-provider-fips /. /usr /usr/lib /usr/lib/x86_64-linux-gnu /usr/lib/x86_64-linux-gnu/ossl-modules /usr/lib/x86_64-linux-gnu/ossl-modules/fips.so /usr/share /usr/share/doc /usr/share/doc/openssl-provider-fips /usr/share/doc/openssl-provider-fips/changelog.Debian.gz /usr/share/doc/openssl-provider-fips/changelog.gz /usr/share/doc/openssl-provider-fips/copyright
There seems to be the validation process, which supposedly must run on each machine it is used on.
openssl fipsinstall -out /tmp/configfile.cnf -module /usr/lib/x86_64-linux-gnu/ossl-modules/fips.so 2>&1 | tee /tmp/result.txt
--
The above are from my notes, and a test run. But I don't see how Redhat is "special" here. If the module loads and cites compliance, you comply.
thayne
3 days ago
> OpenSSL in Trixie is a version supported.
It isn't a validated build. It works the same, but it isn't sufficient if you actually need a validated FIPS module.
> It's just the library, nothing special about the OS.
If you need validation, then the kernel also need to be validated.
Now, it isn't impossible to get a FIPS validated system working with Debian, but you will probably need to contract with another commercial provider like WolfSSL to get validated components. Or compile things yourself. But that is more complicated and involved than just paying for an OS that is validated off the shelf from Ubuntu, Red Hat, or Suse.
tosti
3 days ago
I compile software every day. There's nothing difficult about it until cmake starts complaining, but I've got it back on track every time.
jacobgkau
3 days ago
Companies who care about whether their FIPS implementation is validated or not would probably prefer buying from a company who sells it over relying on a guy at their company to get cmake back on track regularly. At that point, it's not just about the module, it's about custody, liability, etc.
tosti
2 days ago
Jeez laweez. Since when can lawyers make good technical decisions?
I saw a PIN terminal reboot a while ago and the openSSL version was ancient, pretty much historic at that point. But it has an unbroken seal on it, so it's safe, right?
The problem always boils down to money.
thayne
2 days ago
It isn't just compiling something that works. You need to compile it exactly as specified. And document the entire process so you can prove to an auditor that you did everything correctly. Oh, and there's a list of tested platforms, and if your platform isn't on there, which Debian probably isn't, you need to explain to the auditor why it's ok, and why it isn't reasonable for you to use one of the platforms it was tested on.
What you are paying for is not saving the time of a developer compiling something. It's reducing the friction when you go through an audit.
tosti
2 days ago
I wonder what the specifics of certification are. No certificate can ever prove a given binary works correctly. No one really understands how computers work, but here's a piece of paper that says Oracle Linux 11.0 is okay. It was expensive and it has a seal of approval on it, so that proves it.
bubblethink
3 days ago
What is FIPS encryption, why is FIPS unique to RHEL, and what has FIPS got to do with this CVE?
saghm
3 days ago
FIPS is a US government security standard: https://en.wikipedia.org/wiki/FIPS_140
It doesn't have much to do with this CVE, but if you're trying to sell to the US government, it will often be a requirement, which means that a company making money from those sales will not easily be able to move to a distro without that certification.
CodesInChaos
3 days ago
It's about using a certified cryptography implementation. Presumably RHEL has such a certification, while Debian has a compliant but uncertified implementation.
This isn't relevant to the CVE, but counters the claim that Debian is always a suitable choice of distribution.
john_strinlai
3 days ago
>What is FIPS encryption
presumably they mean meeting fips standards https://en.wikipedia.org/wiki/FIPS_140
>why is FIPS unique to RHEL
its not
>what has FIPS got to do with this CVE?
it doesnt. it is brought up in reply to the comment.
pmontra
3 days ago
I planned to install Debian in 2009 and in 2014 but the installer was too hard to use, the desktop in 2009 was ugly (maybe in 2014 too), I could not get a running system that I could use to work. Fast forward to Debian 10, same laptop from 2014, and I got a desktop identical to Ubuntu GNOME.
bigfatkitten
3 days ago
Red Hat is always slow in backporting patches to their Frankenkernel.
exploderate
2 days ago
I don't want to run unstable, just to have recent software.
noir_lord
3 days ago
Debian for hosting anything, Fedora for development desktop.
That's been my rule for years at this point, I think I switched back to debian everywhere after the netplan changeover in ubuntu so somewhere around 17-18 (not against it in principle, just the way they did it in practice).
No real regrets either.
johnnyenn
3 days ago
[flagged]
xnickb
3 days ago
The general advice I've been seeing the past ~8 years is "There is no reason to pick Ubuntu over Debian". I don't know who the opposite advice comes from and why anyone would pick ubuntu for a server.
alexjplant
3 days ago
15-20 years ago the joke was that Ubuntu is a Zulu word that, roughly translated, means "I don't know how to configure Debian". Ubuntu was one of the first distros that allowed one to easily download proprietary WLAN drivers without dealing with the terminal, ndiswrapper, or compiling half-broken OSS implementations; for this reason it caught fire with those who wanted to try Linux but were otherwise unwilling to engage in such shenanigans. I tried it on a laptop around this time and was quite impressed. This reputation for "it just works" has carried them ever since even though other distros now do largely the same thing ( cheap, obscure, or recently-released hardware excepted).
I took the lazy Mint route with my most recent machine since I wanted to use it for light gaming with minimal fuss. I'm going to redo it with Nix sometime soon because the value prop simply isn't there and I'd like to try a declaratively-configured distro.
Tistron
3 days ago
I recently installed NixOS on my thinkpad z16. I set up a sandboxed pi agent to help me configure it and I think it works great. (I also read enough documentation to understand the nix language).
I hade some issues with the trackpad (worse issues that it not being an apple trackpad ie). I told the agent about the problem. It inspected the config, wrote some scripts for me to run outside the sandbox that listened to the trackpad while I used in as per some instructions, and then proceeded to add a few configuration lines that solved to problem. I was pretty impressed (though I think there were maybe 3 back-and-forths with scripts to run, tbh).
benj111
3 days ago
They also sent out free distro CDs. That helped convince me this new fangled Linux thing might be legitimate.
Christ that was 2008.18 years ago. My Linux 'experiment' is old enough to vote
kiicia
3 days ago
I have received cds with ubuntu 5 or 6, was surprised they actually sent those, but at one point I started using it
[edit] omg circa 2006, firefox was still new back then
queenkjuul
2 days ago
I remember installing 5.10 on my family's old Dell on a day off from school in early 2006. I was probably 13.
marcosdumay
3 days ago
More like 20. If I remember it right, by 2007 the Debian community was angry discussing the installation team's decision to include non-free packages in the installation media, what ended the problem of needing a wired connection during the install.
graemep
3 days ago
> Ubuntu was one of the first distros that allowed one to easily download proprietary WLAN drivers without dealing with the terminal, ndiswrapper, or compiling half-broken OSS implementations
None of which was a good reason to use it on servers. Even if you were familiar with Ubuntu there is very little difference between an Ubuntu server and a Debian one.
wolrah
3 days ago
> None of which was a good reason to use it on servers. Even if you were familiar with Ubuntu there is very little difference between an Ubuntu server and a Debian one.
Something to keep in mind is that the term "server" covers a wide range from datacenter beasts pulling kilowatts per node to old desktops running headless to Pi Zeroes and repurposed cell phones, and some of those use cases do in fact benefit from access to proprietary drivers and even hacks like NDISWrapper.
Beyond that, I've seen two main reasons to use Ubuntu Server over Debian, and I say this as someone who has administered Ubuntu, Debian, and CentOS systems for years and always chooses Ubuntu or Debian when the options are open.
1. For a while there were commercial software vendors that would release Linux versions only for specific distros, and Ubuntu was on that list a lot more often than Debian, so if you liked Debian-style packaging and wanted to use commercial software there was a reason to use Ubuntu. Zimbra was one of those when I last used it in the late '00s.
2. There was a time where it seemed like every F/OSS project had a PPA which made it really convenient to install on Ubuntu with automatic updates as part of the system package manager while Debian had to manually load .debs or might not have even had a package due to older system libraries. For personal toy servers and "pet" dev servers this is wonderful, obviously far less important for well-managed "cattle" servers.
Docker, Flatpack, and to a much lesser extent Snap have pretty much eliminated these reasons though. My home server is still Ubuntu LTS because it's easier than changing it but when it next gets rebuilt things will be changing a lot. All of my work servers are migrating to Debian, we have one Ubuntu instance remaining that just had its last major service switched away and a bunch of CentOS systems on sites which are getting swapped out whenever our techs happen to visit.
spider-mario
3 days ago
> Docker, Flatpack, and to a much lesser extent Snap have pretty much eliminated these reasons though.
And also plain Debian repositories gaining popularity over PPAs. WeeChat and Synapse (Matrix) both offer one for example.
wolrah
3 days ago
I wonder how much Raspberry Pi's choice to use Debian as the basis for their default distribution helped here, because it certainly increased the demand for plain Debian packaging of software that was previously packaged for Ubuntu.
graemep
3 days ago
Those are good reasons but lots of people use Ubuntu where neither apply.
queenkjuul
2 days ago
I use it for Livepatch and root-on-ZFS
exploderate
2 days ago
Same for servers. 22 years ago you could install Debian, take it offline while you follow the "Securing Debian Manual" to disable NIS and maybe disallow SSH password logins.
Or you could install Ubuntu which wanted to be secure by default. No open ports in the default install, no shared root password, etc.
Nowadays most of this is common place for distros.
throe937383030
3 days ago
[flagged]
jandrese
3 days ago
I advocated for Ubuntu for years because it was easier to install and had excellent hardware support. For 2026 I have switched back to Debian because Ubuntu has been making my life more difficult. Ubuntu 26 basically forces you onto Wayland even though it breaks some of my use cases, particularly with screen recording. It turns everything into Snaps which is a hassle because it means I need to mirror both the regular repo and the snaps to my closed network instead of just the repo.
Ubuntu still has the superior installer by a good margin, but it does sometimes like to crash when run offline. Debian's installer at least has the option to go text only. There is also more work to do after the install is finished on Debian, but since that's a script it's not such a big deal.
The one bit of the Debian installer I dislike the most is how if you aren't online when you do the install you get a completely empty sources.list, and the Debian sources are a lot more complicated than Ubuntu's. Debian's support for third party drivers like nVidia graphics is also more complicated and confusing than Ubuntu's.
diydsp
3 days ago
Ubuntu is a great starter linux. But you cant live on it, especially in a business.
p91paul
3 days ago
Enterprises love paying for support contracts. If you have one, you can demonstrate something has been accounted for. A secure software without support is worse from an audit perspective than a security disaster with proper paperwork. Most of these people never actually involve support they paid for ever.
notpushkin
3 days ago
> Enterprises love paying for support contracts.
They can pay for Debian support! (I’m not 100% sure who they should go to, but e.g. Freexian are doing Extended LTS for Debian [1], so I suppose they could do a regular support contract as well?)
jacobgkau
3 days ago
> Most of these people never actually involve support they paid for ever.
I've only been in an involved role at one enterprise large enough to pay for support contracts like these, but that one had no trouble getting vendors onto the WebEx while troubleshooting things even if it wasn't clear yet that it was the vendor's fault.
(In fact, they were paying enough that the vendors would actually just hop in to help out with the internal configuration. The most we ever heard were grumblings that we used too high of a priority level on the tickets, but even then, the sentiment from the managers was generally "we're paying for it, and we'll handle those complaints, so do what you need to do to get them on the line.")
xnickb
3 days ago
A quick search shows all sorts of projects choosing Ubuntu. Can you explain a project like mail-in-a-box going with it? And 5.15 kernel at that..
voakbasda
3 days ago
People make bad choices all the time for many different reasons. Usually, “it seemed like a good idea at the time” is at the top of that list.
bityard
3 days ago
But by definition it wasn't a bad choice (or a mistake) if it seemed like the right choice given the information available at the time. Unless you have some sort of crystal ball the rest of us don't.
voakbasda
2 days ago
A choice that turned out badly after reflection of hindsight was not in fact good. At best, it was ignorant; at worst, negligent. Regardless, unavoidable; as you surmise, no one has a crystal ball.
bityard
3 days ago
I deployed Ubuntu on a LOT of servers 10 years ago because at the time, they had a track record of doing good things in, with, and for, the Linux and open source community. I had already been using it on the desktop for a long time by that point and knew it well. Ubuntu was far and away the most popular; it was a very safe and sane choice.
That changed when they started heavily promoting Snaps as the next big thing and started putting features and updates behind their enterprise offerings. Basically, they stopped being "Debian, but better." And Debian also made lots of incremental improvements in user-friendliness in that time. Basically, Debian is now pretty much what Ubuntu always promised to be.
BoppreH
3 days ago
Platform support. Oracle Cloud for example only provides images[1] for Oracle Linux, RHEL, Ubuntu, and Windows Server. Anything else you have to bring your own.
[1] https://docs.oracle.com/en-us/iaas/Content/Compute/Reference...
rezzo
3 days ago
If I try to create a new instance on Oracle Cloud, these are the options: Oracle Linux, Ubuntu, RHEL, (CentOS), Windows Server, AlmaLinux, Rocky Linux.
Anyway you are right, I would have switched already if Debian was available. I guess AlmaLinux could be an option to consider, since I've read in another comment that they've patched ahead of upstream for several vulnerabilities this year.
kqgnkqgn
3 days ago
For x86_64, It's relatively easy-ish to upload your own Debian image, from Debian's generic cloud QCOW2 image, and it works just fine. I think ARM needs a bit more work if I remember correctly.
(But 100% agree this shouldn't be necessary).
tannhaeuser
3 days ago
This. For llama-cpp and stable-diffusion-cpp, you get official builds only for Ubuntu 24.04 LTS and Win and MacOS. If you want to run ROCm, support is available in the form of an irreversible install script that wrecks any amdgpu driver install and requires run level 3 ie. without GUI. Good luck with running that on anything other than the exact Ubuntu release it was created for.
avadodin
2 days ago
Let's be honest. Pre-built binaries. Yeah. Probably shame the project into releasing the SteamOS version on Steam.
sgarland
3 days ago
The only recent reason I’ve managed to come up with is it far and away has the best support for Nvidia’s various drivers and utilities for running GPUs and its assorted ecosystem, like Infiniband and Spectrum-X Ethernet.
If there’s another option I’m unaware of, I’d love to hear it. Also to be fair, I didn’t evaluate Sid for this, only Stable.
27183
2 days ago
Certain AMD graphics drivers require specific Ubuntu releases and versions. I guess one might reasonably ask "why would you run AMD graphics drivers?" to which I don't really have a good answer. But that's why I run an Ubuntu box ;p. I'd so much rather be running Alpine.
gambiting
3 days ago
I've set up a new server literally couple weeks ago on a droplet on Digital Ocean - Ubuntu LTS is the default choice(you can select other distros but Ubuntu is the default). So I guess I picked Ubuntu because I haven't done Linux admin in over a decade and it's presented as the default choice by a big cloud provider.
queenkjuul
2 days ago
Despite the recent hate, Ubuntu is still serving me very well on all of my servers.
vbezhenar
3 days ago
What's your recommendation nowadays?
genxy
3 days ago
Debian
BoppreH
3 days ago
The more I look at this the angrier I get. This is a CVE that Anthropic claims can get a Remote Code Execution on vulnerable systems, which includes default Ubuntu installs running any sort of Go server like Caddy. Bad enough that I shut down my personal website and self-hosted tools (sorry for any typos, my grammar checker is also down).
And this is how Ubuntu describes the vulnerability to sysadmins:
In the Linux kernel, the following vulnerability has been resolved:
ipv4: free inet_opt and ireq_opt after an RCU grace period
tcp_v4_syn_recv_sock() transfers ownership of ireq->ireq_opt to the
child socket (newinet->inet_opt) without copying it.
Another cpu can concurrently process a retransmitted SYN for the same
request socket, and send a SYNACK from tcp_check_req().
tcp_v4_send_synack() and inet_csk_route_req() read ireq->ireq_opt
under rcu_read_lock() only, and ip_build_and_send_pkt() and
ip_options_build() then read opt->optlen twice.
Note that the SYNACK timer itself is not an issue: it holds a
reference on its request socket, and inet_csk_reqsk_queue_drop()
calls timer_delete_sync() before the child can be freed.
Since commit 079096f103fa (“tcp/dccp: install syn_recv requests
into ehash table”), request sockets are processed without holding
the listener lock, so nothing prevents the child socket from being
freed while the SYNACK is still being built. TCP child sockets do
not have SOCK_RCU_FREE, and inet_sock_destruct() frees inet_opt
with a plain kfree(), leading to a use-after-free in
ip_options_build().
A similar issue exists with request socket migration
(net.ipv4.tcp_migrate_req=1, or a BPF_SK_REUSEPORT_SELECT_OR_MIGRATE
program). reqsk_timer_handler() clones the request socket with
inet_reqsk_clone(), so that the old request socket and its clone
share the same ireq_opt, then reqsk_migrate_reset() clears the
pointer in the old one. Another cpu holding a reference on the old
request socket can still be using these options (sending a SYNACK,
or creating a child in tcp_v4_syn_recv_sock()) when the clone is
freed, and tcp_v4_reqsk_destructor() also uses a plain kfree().
Readers already use RCU, and other paths replacing inet_opt
(do_ip_setsockopt(), cipso_v4_sock_setattr()...) already use
kfree_rcu(). Use kfree_rcu() in inet_sock_destruct() and
tcp_v4_reqsk_destructor() as well.
IPv6 is not affected by the first issue, because tcp_v6_syn_recv_sock()
duplicates the options. tcp_v6_reqsk_destructor() has the same
migration issue with ipv6_opt, which is only set by CALIPSO. This
will be addressed in a separate patch.
How is this in any way, shape, or form acceptable two weeks after the CVE was published?reaperducer
3 days ago
sorry for any typos, my grammar checker is also down
I assume this is unrelated to the Ubuntu situation, but how does a grammar checker go down? We've been doing offline grammar checking since computers had 64K of RAM.
BoppreH
3 days ago
Self-hosted LanguageTool server[0] with browser addon. 18 gigabytes of n-gram data plus machine learning models. You can catch tpyos on 64K of RAM, but not any deep grammar mistakes, un-idiomatic phrases, or mistakes in common proper names.
thatonehack
3 days ago
Sounds like a lot of heavy lifting for something that is maybe slightly better than spell checking 25 years ago.
eichin
3 days ago
Grammatik ran in 64K of RAM on a Z80 running CP/M. (The binary included a Forth interpreter so there was a lot of straight up code compaction.) So yeah, you could catch a lot of common English-language infelicities in a startlingly resource constrained environment... in 1983. Certainly a lot more than typos.
(The reason I remember this bright and shiny data point is I spent a week or three reverse engineering it and getting access to the inner interpreter; the office staff actually used it, though.)
SSLy
3 days ago
consider harper instead. I'm using it right now and it highlighted first two words of this comment. https://writewithharper.com/
lstodd
3 days ago
/o\ all this just for what exactly?
Dylan16807
3 days ago
To make fewer grammar mistakes.
At one point that was less than $100 of RAM which isn't a big deal for the trade.
BoppreH
3 days ago
Oh, the 18 gigabytes is not RAM, it's the storage. Language Tools indexes into the n-grams, so it doesn't have to keep everything in memory.
unrented7977
3 days ago
If you're asking a self-hoster "why" then you are asking the wrong question
lstodd
3 days ago
well, yes. sorry.
I should have asked what is it there in replacing yourself with a mishmash of external world.
SSLy
3 days ago
there's much more to writing voice than sticking with terrible usage.
StilesCrisis
3 days ago
[dead]
user
3 days ago
ranger_danger
3 days ago
> running any sort of Go server like Caddy
It's so much worse than this, and there is a staggering amount of misinformation running rampant about this bug.
MPTCP is not a requirement, it can be exploited merely by sending specially crafted TCP packets with (any) IP options set. No special MPTCP support, web servers or any specific software listeners are even necessary at all to trigger it, just send the packets and boom.
I think the reason people assume MPTCP is a requirement is because that's what the PoC used... but MPTCP itself also doesn't even rely solely on IP options.
Ubuntu also does not even list a single mitigation strategy... at least RHEL did.
And like I said, any normal TCP packet that contains IP (not TCP) options can trigger the bug. I cannot emphasize enough how important and absolutely ridiculous this is.
Like the post says, this is big enough to get a massive amount of people to completely stop trusting Ubuntu entirely and jump ship.
xet7
2 days ago
> Ubuntu also does not even list a single mitigation strategy...
I installed newest Ubuntu mainline kernel, it did work for me:
https://kernel.ubuntu.com/mainline/v7.3.1/
I also did patch my FLOSS Go software:
https://github.com/wekan/wekan/commit/e9751b65d4
I'm maintainer of WeKan FLOSS kanban https://wekan.fi , https://github.com/wekan/wekan , and maintainer of FerretDB v1 fork https://github.com/wekan/FerretDB . There is also WeKan Snap package https://snapcraft.io/wekan/ .
But I don't work for Ubuntu, I don't have any answers why Ubuntu does not do something.
xet7
2 days ago
Someone from Canonical answered about kernel:
rtp4me
3 days ago
I have some publicly facing web servers running Debian and Ubuntu. Specifically, what can I do to test and see if my servers are vulnerable?
harshreality
3 days ago
Debian (trixie kernel) 6.12.113 was allegedly patched for this bug, but there's also a .115 that's been released in the last few days, upgrade to that and reboot.
For Ubuntu (which I don't use), you'd need a 3rd party updated kernel repo, to use a patched kernel from that.
It's not an instantaneous exploit; it apparently takes a lot of iteration over the network. A lot of cloud network providers are mitigating it by dropping options at the border, but unless you test and confirm that, you should assume it's possible for a motivated-enough attacker to compromise your server.
xmodem
3 days ago
At least for 26.04, there is a 7.0.0-43 kernel available in the -proposed repos that has the patch. Presumably planned to be made availalbe any month now.
https://wiki.ubuntu.com/Testing/EnableProposed
https://launchpad.net/ubuntu/resolute/amd64/linux-headers-ge...
collinmanderson
3 days ago
> I already had a bad feeling the first time I saw "Get more security updates through Ubuntu Pro" on `apt upgrade`, this is now the kick I needed to move to a different distro.
To be clear, Ubuntu Pro doesn't have the fix yet either.
neya
3 days ago
Moved to Debian few years back and never looked back. We used Ubuntu for a bunch of clients and unfortunately had to let them know they will have to migrate to Debian or similar. It's such a shame because I really used to love Ubuntu until Canonical started turning slowly into your typical everyday corporate.
flaburgan
3 days ago
As far as I know the only working exploit is working on machine with MultiTCP enabled. Redhat also downgraded the issue to "high" and also did not release a patch yet. I would have preferred a patch but I accept that they know better than me what they are doing.
garbagecreator
3 days ago
Why would they take so long anyway and be behind volunteer run projects like debian? Is it something about corporate shenanigans and testing? because afaik in fedora for example firefox is always behind in security updates compared to debian.
qsfp28
3 days ago
[dead]
cozzyd
3 days ago
RHEL did release a new kernel. Presumably it has the fix (though I guess I didn't actually check)
klooney
3 days ago
They're totally asleep at the wheel, it's malpractice. The pitch for RHEL is highly competent maintenance you can't get elsewhere
InsidiousWombat
3 days ago
RHEL also dropped a ball on it so yeah the alternative for paying for RHEL license is apparently "just use Debian or hire some Arch nerds"
DetroitThrow
3 days ago
Is RHEL really unpatched still? Looks like patches came yesterday: https://access.redhat.com/security/cve/cve-2026-98432
BoppreH
3 days ago
Thanks, I removed that part from my comment. Still, that's two weeks late.
DetroitThrow
3 days ago
>Still, that's two weeks late.
Agreed! I know this is a bad month, but this is poor form from several vendors that tout "we'll handle XYZ aspect of security for you".
collinmanderson
3 days ago
> I already had a bad feeling the first time I saw "Get more security updates through Ubuntu Pro" on `apt upgrade`
To be clear, Ubuntu Pro doesn't have the fix yet either, in case anyone's confused.
BoppreH
2 days ago
This was an old gripe unrelated to today's issue. But your clarification is exactly why it left a bad feeling back then, the message certainly implies that my system is not getting all the security updates it could get.
bayindirh
3 days ago
I believe RHEL/Alma/Rocky has released patches today. I have a notice about they have done so.
lozf
3 days ago
Alma released a patch ahead of upstream again, just like they did for several other critical vulnerabilities this year.
dp-hackernews
3 days ago
I use NixOS btw