Tip: Install a Chromium flavor browser (Chromite) separate from the main browser.
Disable Javascript and hardware accelerated video decoder (commonly exploited) from the flags page and enable reader mode to fix broken JS-dependent websites when browsing blogs and random sites on your personal devices, else dedicate a tablet.
I've been noodling with porting the kernel exploit to other devices, and the exploit is very sensitive to how the compiler happens to lay out stack frames, which varies between kernel builds. Once you figure out the right "stamp method" and offsets for a particular kernel build though, it's fairly reliable.
Thanks for testing, we currently only tested it on Pixel 10, but there are a few people on our repo creating PR to support other devices, you can take a look here https://github.com/NebuSec/CyberMeowfia
They are a security boundary. The fact that you need a vulnerability to escape them is proof of that. They just don't have a particularly high cost of escape because reachable kernel vulnerabilities are so common.
Runpod, digital ocean's gpu cloud, and at least a few others use Linux containers for isolation between tenants (look at Wiz's blog post about the nvidia container toolkit bug; digitalocean just puts everyone in a massive k8s cluster)
> This is the same shape as many other life-cycle bugs [...]
Claude-ism detected. IME with Claude Code an object does not have a type or definition, apparently, but rather a shape (or at least it reaches for that word before more technically-accurate ones). Problems are not of a similar class or type, but of the same shape. Functions are not defined by their signatures but by their shape. Who talks like this and how did it make its way into the training data so pervasively?
I think you're probably right that the article was AI-assisted, but (if so) it's important not to confuse that property of the article with the thing the article is about. Google wouldn't pay $90k for a hallucination.
I don't mean that as a criticism—the question of how to receive AI-processed content is a huge one that is in a state of chaotic turbulence right now. I'm working on a post about that over here: https://news.ycombinator.com/item?id=48887149.
Btw, Nebula Sec is a YC startup in the current batch. We've been working with them on how to launch on HN, and one of the things I've been trying to explain is that the HN audience won't respond well to LLM-generated reports. The underlying work, though, is very impressive. These guys know what they're doing—the OP is by no means their only significant find—and the fact that they're doing it with an agent, rather than the traditional way, is significant.
A thing that notably triggers my allergies is that if significant human effort went into something, a few paragraphs written by a human seems like a trivial additional investment; if that last touch is missing, it's really hard for me to extend the benefit of the doubt that there really is something there.
Obviously this is only one signal among many, one that can be overruled, but the ick remains regardless.
It's not so widely used and it's not explained in the first couple screenfuls of TFA (which by itself is weirdly structured, taking entire paragraphs to explain when it was introduced, when it was discovered, etc. before even explaining what it actually is).
Of course the title was chosen when the article was first published on a site dedicated to security, where probably everyone knows it. This suggests that insisting on unmodified titles when republishing in HN is a poor rule.
Has anyone in infosec ever seen the term "use after free" before LLMs? Or is this basically an acronym claude invented? I say this because I see claude use this term all the time like its common knowledge but in 15+ years in tech never seen it myself. I've seen all kinds of terms used to describe memory errors: memory corruption, heap corruption, stack corruption, whatever, just never this acronym.
This is and has been a common term in any systems programming concept for decades. You can, for example, search CVEs and easily find some from over 15 years ago: https://www.cve.org/CVERecord?id=CVE-2010-1119
It was even enumerated in the first pass of CWE as CWE-416 in 2006.
Yes, it was a common attack vector in binary exploitation. Heap based attack vector like use after free, double free, heap overflows, and others are pretty neat. They force you to learn a lot about how malloc works.
There is a lot of cool work that went into making memory allocation work well; the different arenas, fast bins, chunk headers, etc. are super cool.
if you have spend any amount of time in low level c vulnerabilities you will have heard about it, it is a very common time on the low level/cybersec space.
Huh? That is a really common term. There have been even memes about it. I remember roughly 5 years ago I first heard the ironic; "Real men use after free" in a discussion about Rust's benefits as its borrowing checker would have also prevented this one.
"Use after free" is also described in most standard books about C as a thing you should never do, have you read one?
Please don't be snarky or cross into putdowns or personal attack. We're all in (let's call it) the unlucky 10,000 about something. About most things actually.
There is an interesting episode of This American Life about how everyone, everyone, has weird gaps in their knowledge that eventually get filled in sometimes fun or humiliating ways. You have these too.
Hey guys - please don't do tit for tat spats on HN. I know how it feels (believe me, I know how it feels down to such a level that any hypothetical offspring would also know how it feels), but it only makes everything worse.
Hey guys - please don't do tit for tat spats on HN. I know how it feels (believe me, I know how it feels down to such a level that any hypothetical offspring would also know how it feels), but it only makes everything worse.
>Google has rewarded us $92,337 in kernelCTF
I'm all ears now
Seems low considering the wide impact, but maybe the only thing corporations throw big money at is remote exploits?
That's a huge amount of money for a vulnerability.
Tested on three Android devices (version 9, 13, 16) with different Firefox versions under 150 (had to modify for older).
Two boot looped, I had to enter recovery and the other just powered off [0].
The demo modifies the wallpaper on supported Pixel devices.
[0] IonStack https://rootme.nebusec.ai
____
Tip: Install a Chromium flavor browser (Chromite) separate from the main browser.
Disable Javascript and hardware accelerated video decoder (commonly exploited) from the flags page and enable reader mode to fix broken JS-dependent websites when browsing blogs and random sites on your personal devices, else dedicate a tablet.
I've been noodling with porting the kernel exploit to other devices, and the exploit is very sensitive to how the compiler happens to lay out stack frames, which varies between kernel builds. Once you figure out the right "stamp method" and offsets for a particular kernel build though, it's fairly reliable.
Thanks for testing, we currently only tested it on Pixel 10, but there are a few people on our repo creating PR to support other devices, you can take a look here https://github.com/NebuSec/CyberMeowfia
fwiw, the firefox vulnerability seems to be CVE-2026-10702 (type confusion in the ionmonkey jit compiler): https://www.sentinelone.com/vulnerability-database/cve-2026-...
Daaaaamn: "GhostLock was introduced in Linux 2.6.39 and fixed in Linux 7.1."
2.6.39? That's really going back a ways. It's great to hear that GhostLock is already fixed in 7.1.
Forgot to include "LPE" (local...) in the title so most of us can get back to weekending.
Since this enables container escape, sounds like this might still impact quite a lot of us?
I guess, if you thought Docker/etc. was a security boundary
They are a security boundary. The fact that you need a vulnerability to escape them is proof of that. They just don't have a particularly high cost of escape because reachable kernel vulnerabilities are so common.
Runpod, digital ocean's gpu cloud, and at least a few others use Linux containers for isolation between tenants (look at Wiz's blog post about the nvidia container toolkit bug; digitalocean just puts everyone in a massive k8s cluster)
I know there's a lot you can do in k8s to mitigate it, but I didn't think that prevented it outright.
A lot of us rely on Linux containers' being escape-proof?
I would have hoped that only a few of us are so misinformed as to do that.
they also found a type confusion in firefox/ionmonkey, so you can go from random website to pwned very quickly.
> This is the same shape as many other life-cycle bugs [...]
Claude-ism detected. IME with Claude Code an object does not have a type or definition, apparently, but rather a shape (or at least it reaches for that word before more technically-accurate ones). Problems are not of a similar class or type, but of the same shape. Functions are not defined by their signatures but by their shape. Who talks like this and how did it make its way into the training data so pervasively?
I think you're probably right that the article was AI-assisted, but (if so) it's important not to confuse that property of the article with the thing the article is about. Google wouldn't pay $90k for a hallucination.
I don't mean that as a criticism—the question of how to receive AI-processed content is a huge one that is in a state of chaotic turbulence right now. I'm working on a post about that over here: https://news.ycombinator.com/item?id=48887149.
Btw, Nebula Sec is a YC startup in the current batch. We've been working with them on how to launch on HN, and one of the things I've been trying to explain is that the HN audience won't respond well to LLM-generated reports. The underlying work, though, is very impressive. These guys know what they're doing—the OP is by no means their only significant find—and the fact that they're doing it with an agent, rather than the traditional way, is significant.
A thing that notably triggers my allergies is that if significant human effort went into something, a few paragraphs written by a human seems like a trivial additional investment; if that last touch is missing, it's really hard for me to extend the benefit of the doubt that there really is something there.
Obviously this is only one signal among many, one that can be overruled, but the ick remains regardless.
Isn't this just observation bias? "If I haven't encountered something, then it must not be real?" (Paraphrasing)
A what?
Use after free?
Thanks! I've put that in the toptext now.
I'm glad someone else asked. :)
It's not so widely used and it's not explained in the first couple screenfuls of TFA (which by itself is weirdly structured, taking entire paragraphs to explain when it was introduced, when it was discovered, etc. before even explaining what it actually is).
Of course the title was chosen when the article was first published on a site dedicated to security, where probably everyone knows it. This suggests that insisting on unmodified titles when republishing in HN is a poor rule.
Not that everyone should know it but it's definitely widely used. A Google search for "stack UAF" also turns it up.
Has anyone in infosec ever seen the term "use after free" before LLMs? Or is this basically an acronym claude invented? I say this because I see claude use this term all the time like its common knowledge but in 15+ years in tech never seen it myself. I've seen all kinds of terms used to describe memory errors: memory corruption, heap corruption, stack corruption, whatever, just never this acronym.
This is and has been a common term in any systems programming concept for decades. You can, for example, search CVEs and easily find some from over 15 years ago: https://www.cve.org/CVERecord?id=CVE-2010-1119
It was even enumerated in the first pass of CWE as CWE-416 in 2006.
Yes, it was a common attack vector in binary exploitation. Heap based attack vector like use after free, double free, heap overflows, and others are pretty neat. They force you to learn a lot about how malloc works.
There is a lot of cool work that went into making memory allocation work well; the different arenas, fast bins, chunk headers, etc. are super cool.
if you have spend any amount of time in low level c vulnerabilities you will have heard about it, it is a very common time on the low level/cybersec space.
It has been a known bug class for quite some time.
yes, it’s a very common term in infosec. I haven’t heard the “UAF” acronym before though
Huh? That is a really common term. There have been even memes about it. I remember roughly 5 years ago I first heard the ironic; "Real men use after free" in a discussion about Rust's benefits as its borrowing checker would have also prevented this one.
"Use after free" is also described in most standard books about C as a thing you should never do, have you read one?
I haven't really seen it as an acronym "UAF", but I can't recall the first time I heard "use after free". It was probably in the previous century.
The idea that Claude came up with it is ridiculous.
You have somehow lived in a strange bubble.
2025: https://redis.io/blog/security-advisory-cve-2025-49844/ 2023: https://seclists.org/oss-sec/2023/q2/133 2022: https://www.zerodayinitiative.com/advisories/ZDI-22-1690/ 2014: https://ftp.openbsd.org/pub/OpenBSD/patches/5.4/common/008_o...
It's an issue as old as time, or thereabouts.
[flagged]
Please don't be snarky or cross into putdowns or personal attack. We're all in (let's call it) the unlucky 10,000 about something. About most things actually.
https://news.ycombinator.com/newsguidelines.html
There is an interesting episode of This American Life about how everyone, everyone, has weird gaps in their knowledge that eventually get filled in sometimes fun or humiliating ways. You have these too.
Wow, what is that episode? I haven't listened to TAL in probably more than a decade but it was great for a long time, and for all I know still is.
"A Little Bit of Knowledge"
I can see that you're old and that I'm older, but I fail to see the justification for being snarky about that.
~ https://news.ycombinator.com/newsguidelines.html[flagged]
And a wrong justifies a wrong?
These are the times we make.
[flagged]
[flagged]
I understand the response (hence https://news.ycombinator.com/item?id=48887373) but please don't react by breaking the site guidelines yourself. That only makes things worse.
https://news.ycombinator.com/newsguidelines.html
[flagged]
Hey guys - please don't do tit for tat spats on HN. I know how it feels (believe me, I know how it feels down to such a level that any hypothetical offspring would also know how it feels), but it only makes everything worse.
https://news.ycombinator.com/newsguidelines.html
[flagged]
Hey guys - please don't do tit for tat spats on HN. I know how it feels (believe me, I know how it feels down to such a level that any hypothetical offspring would also know how it feels), but it only makes everything worse.
https://news.ycombinator.com/newsguidelines.html