I feel as though this should be googlebrotli2shell, not http2shell. Google deserves to take a bit of a reputational hit for this. This is a basic memory safety violation, from the same organization that does wuffs, that promotes Rust for memory safety, that has Carbon. zstd has high quality rust implementations and is from roughly the same time.
On top of that, the brotli library saw no releases for almost a full year, with the fix for this vulnerability being committed back in February. Google builds from main for all their projects, so were unaffected, but open source releases are a complete afterthought. Over 100 commits with miscellaneous fixes left languishing until a security incident forces a release.
This one again feels overblown, at least for servers. I just checked an org of over 200 GitHub repos. Node, Python, and C#. None of them are vulnerable... because none of them actually call the Brotli decoder. It's just not enabled by default on the server side, by the platforms themselves. This is much like the PHP bugs, where specific conditions have to be in play before you're actually vulnerable.
For clients? Sure, that's a bigger risk. Patch them. But bad guys aren't attacking your clients unless the clients connect to them. Don't stay up late to fix this.
(And yes, .NET is included here, because Microsoft's Brotli module is a binding for Google's vulnerable reference implementation.)
I can't find download numbers for extras, but it comes in the pretty dang innocuous-seeming `aiohttp[speedups]`, as well. Also `urllib3[brotli]`. Many, many people will be running these servers without recognizing the name of the library, especially in the agentic era.
I might be missing something obvious in your message, cause I don't see why server/client is relevant. Why would a frontend app speak a protocol that the backend doesn't?
That's just the total number of times that package was downloaded, which is completely unrelated to how many servers it appears in? Same with `aiohttp`: aiohttp can be used as a client library.
Sure, people should check their dependency trees, and make informed decisions.
The whole package manager system is a complete disaster. A huge number of dependencies are pulled in that go unused in most projects, so the number of downloads is an extremely unreliable number. I'd be surprised if more than 10% of those downloads actually use the brotli decoder.
We should start naming them like hurricanes: NIST creates a list of alphabetical names and assigns any CVE >= 9.0 with a name. Vulnerability Alex (CVE 9.4)
Had a short moment to glance at it. My guess would be BROTLI_DCHECK(s>meta_block_remaining_len <= (int)BROTLI_BLOCK_SIZE_CAP) along with BROTLI_SAFE_WITH_STATUS having that goto saveStateAndReturn on non BROTLI_DECODER_SUCCESS.
I feel like normal security issues don't get much publicity. The PHP and eMudhra issues seemed severe, and worth publicity. But then with things like this, I'm not sure. Is this a severe issue? Or is it just a run of the mill issue that's only newsworthy because web security is on people's minds right now?
The whole industry is on edge right now, and numbers wise the CVE count has exploded beyond belief. It's probably to take the side of caution, treat everything as important and update everything promptly rather than the old way of doing things where libraries are left months or years out of date until something happens.
> I's probably to take the side of caution, treat everything as important and update everything promptly
The risk is that if people keep seeing headlines about some vuln emergency that isn't in fact exploitable in most cases they'll just start to ignore them.
I am just amazed at how many people are blind to this.
Every single time one of these labs does something it is almost always sensationalized. They absolutely cannot refrain from describing how incredible their models are, it has to be injected into everything. I get this is basic grow-your-company stuff but it is getting obnoxious.
I think — and this is not at all a criticism of your comment — that we all have to urgently get out of the habit of calling them “labs”, because in this way we reinforce their ability to portray themselves as sort of scientifically neutral observers of what is happening. I make this error all the time and I am trying to stop.
Though I got told off for saying it maybe too snarkily, I also think that when well-paid, high-profile employees of one of these LLM as a service companies post in controversial or notable ways that could affect the perception of their employer’s products, we should consider that they are acting as a spokesperson. Any tweet where you might think “do I need to consider how this relates to my employer’s SEC filings” is PR. Just because they are acting in informal ways doesn’t mean it’s personal opinion; we shouldn’t give it maximum benefit of the doubt.
Similarly, I think we have to consider that Patch The Planet may be vulnerable to perverse incentives.
And this commit contained a refactoring from BROTLI_BOOL to BrotliDecoderErrorCode so the situation was that probably one of the error conditions previously simply returned false but needed more detail about what went wrong to continue safely.
Well okay this change from `if (prev_ix < cur_ix)` to `if (prev_ix < cur_ix && cached_backward <= max_backward)` is also suspicious and could be an related or unrelated hardening fix.
Apparently it doesn't contain a binding to the C library, but it does contain some compatibility and shares design decisions with it. In other words, it's not a clean-room implementation from the spec, but rather it's a port. Since this RCE is triggered by a OOB access, it's unlikely to have made it into the crate, but it's good to keep these things in mind.
The real killer is the oath crate. Basically every rust project using OAuth is vulnerable. That's 398 projects on crates.io plus who knows how many binaries (a lot of non-library projects don't bother publishing to crates.io).
Another scary one is "a practical HTTP client that is fun" https://lib.rs/crates/isahc used in 317 crates including sequoia. In case you wanted somebody to steal your private keys.
I would love to hear your definition of this. Are llms used to aid in incident response? 100%. Why would I sit there and manually review data from multiple sources when I could have an agent pull from all and summarize? But to hand it off end to end? I haven't seen anyone accomplish this.
> We will support the Deno runtime for another year with monthly releases containing bug fixes and security updates. After that year we will end our development
I know that it is dead but since they provide security updates for another year I haven’t migrated off of it immediately. Anyways, the Deno runtime uses a brotli Rust crate that does not wrap C code, and with unsafe off, so I assume it is safe.
Only decompression with Google's brotli library is affected. So if you use "Brotli" or "brotlicffi" in your Python app to decompress brotli, you're vulnerable. Compressing responses with brotli from Apache is safe.
If you are using Python, you are affected if you use urllib3, requests, httpx, aiohttp, Scapy, and others, if they were installed when Brotli was also installed. You can mitigate by uninstalling brotli and brotlicffi, OR, strip `br` from Accept-Encoding on outbound AND reject `Content-Encoding: br` on inbound.
This is not a server-side issue (unless for some weird reason you're using Brotli decoding in your http request processing), it's client-side.
The brotli commit under this is a state fix more than a bounds fix: DecodeBlockTypeAndLength used to return BROTLI_FALSE for both "needs more input" and "format error", so a stream truncated at a block-switch boundary is reported as invalid, and a caller that branches on that can be walked into the wrong path. The commit gives the function a BrotliDecoderErrorCode, adds a distinct BLOCK_SWITCH format error and keeps NEEDS_MORE_INPUT for the truncated case (google/brotli 0ed4268).
Worth checking before the panic: node vendors that decoder in deps/brotli, and its v24.x tree already carries the changed function, so 24.x is not exposing the old behaviour. What is exposed is anything still vendoring brotli from before February 2026, and "disable br" is a fine stopgap that leaves the decoder in place.
From the honeypot side, an HTTP/1.1-only decoy farm is blind to this class. Mine is: no h2 preface in 7,900 lines, so the sweepers can't tell me whether anybody is already trying it.
On top of that, the brotli library saw no releases for almost a full year, with the fix for this vulnerability being committed back in February. Google builds from main for all their projects, so were unaffected, but open source releases are a complete afterthought. Over 100 commits with miscellaneous fixes left languishing until a security incident forces a release.
For clients? Sure, that's a bigger risk. Patch them. But bad guys aren't attacking your clients unless the clients connect to them. Don't stay up late to fix this.
(And yes, .NET is included here, because Microsoft's Brotli module is a binding for Google's vulnerable reference implementation.)
I can't find download numbers for extras, but it comes in the pretty dang innocuous-seeming `aiohttp[speedups]`, as well. Also `urllib3[brotli]`. Many, many people will be running these servers without recognizing the name of the library, especially in the agentic era.
I might be missing something obvious in your message, cause I don't see why server/client is relevant. Why would a frontend app speak a protocol that the backend doesn't?
Sure, people should check their dependency trees, and make informed decisions.
I actually kinda like how that works.
The python package has already been updated to 1.2.1. https://pypi.org/project/brotli/1.2.1/
Another day another out of bounds access in C code.
The risk is that if people keep seeing headlines about some vuln emergency that isn't in fact exploitable in most cases they'll just start to ignore them.
https://nitter.jaydenha.uk/OpenAI/status/2113766354386084338
Every single time one of these labs does something it is almost always sensationalized. They absolutely cannot refrain from describing how incredible their models are, it has to be injected into everything. I get this is basic grow-your-company stuff but it is getting obnoxious.
Though I got told off for saying it maybe too snarkily, I also think that when well-paid, high-profile employees of one of these LLM as a service companies post in controversial or notable ways that could affect the perception of their employer’s products, we should consider that they are acting as a spokesperson. Any tweet where you might think “do I need to consider how this relates to my employer’s SEC filings” is PR. Just because they are acting in informal ways doesn’t mean it’s personal opinion; we shouldn’t give it maximum benefit of the doubt.
Similarly, I think we have to consider that Patch The Planet may be vulnerable to perverse incentives.
And this commit contained a refactoring from BROTLI_BOOL to BrotliDecoderErrorCode so the situation was that probably one of the error conditions previously simply returned false but needed more detail about what went wrong to continue safely.
Well okay this change from `if (prev_ix < cur_ix)` to `if (prev_ix < cur_ix && cached_backward <= max_backward)` is also suspicious and could be an related or unrelated hardening fix.
Aren't you glad cargo connects to the network whenever it feels like it? I just love it when my build tool does that.
There are 753 crates that drag in brotli this way: https://lib.rs/crates/curl/rev
The real killer is the oath crate. Basically every rust project using OAuth is vulnerable. That's 398 projects on crates.io plus who knows how many binaries (a lot of non-library projects don't bother publishing to crates.io).
Another scary one is "a practical HTTP client that is fun" https://lib.rs/crates/isahc used in 317 crates including sequoia. In case you wanted somebody to steal your private keys.
and this is the actual CVE report, which doesn't say much: https://www.cve.org/CVERecord?id=CVE-2026-111497
Is it really so hard to write a 2 sentence tweet that you need an AI to do it for you?
> We will support the Deno runtime for another year with monthly releases containing bug fixes and security updates. After that year we will end our development
https://deno.com/blog/cloudflare
https://x.com/AikidoSecurity/status/2113759110625906950
whether a hello wolrd in fastapi is affected might also be interesting
This is not a server-side issue (unless for some weird reason you're using Brotli decoding in your http request processing), it's client-side.
Thank you Paul for the write-up (https://opensourcemalware.com/blog/node2shell-affects-python)
Worth checking before the panic: node vendors that decoder in deps/brotli, and its v24.x tree already carries the changed function, so 24.x is not exposing the old behaviour. What is exposed is anything still vendoring brotli from before February 2026, and "disable br" is a fine stopgap that leaves the decoder in place.
From the honeypot side, an HTTP/1.1-only decoy farm is blind to this class. Mine is: no h2 preface in 7,900 lines, so the sweepers can't tell me whether anybody is already trying it.
That's pretty difficult if you make outbound requests, and don't already have a TLS interception proxy set up.
https://news.ycombinator.com/item?id=50069499
Edit: why flagged
Rust Derangement Syndrome is at epidemic levels here.
[1] When more than half of the "standard" https://www.rfc-editor.org/info/rfc7932/#page-44 is an opaque binary blob, they're really not encouraging independent implementations.
Edit: the votes really show what an echochamber for Big G this place has become. FUCK YOU, GOOGLE!