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I received 9 reports of Fil-C issues from Anthropic

All of them were real bugs. None of them were false positives.

The quality of the reports was exceptional. (My baseline is doing security defense on a browser engine, so my baseline has a large sample count and is probably representative of what experts are capable of.)

The quality of the proposed fixes was alright. I took some of the fixes verbatim. I used most of the fixes as significant inspiration for doing it my way.

The quality of the test cases was exceptional.

Maybe I’m special somehow! But I just want to call out the enormous chasm between what I saw of anthropic’s capability and what TFA says

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A simple reason could be the age of the codebase. New code contains more serious bugs, and younger projects are made up of more new code than more mature projects. In older code, especially well-used older code, many serious issues have already been found and fixed.
It’s not a reason for the wide chasm though.

If you told me that some significant number of Ant findings were duds, then I could reconcile that with what I saw first hand.

But TFA is making a more extreme statement

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That's interesting. While the curl maintainer seems to have been underwhelmed with Mythos 5 in particular, it looks like he also backs up your account of high-quality AI reports (although unclear if these come from Glasswing or elsewhere) at this point.

> The slop is gone

> A sizeable portion of users seem to still believe we still suffer from a lot of made up and hallucinated reports by these AIs. We really don’t.

> Almost all the stupidity and lies we saw in the vulnerability reports made by AIs in the past have ceased. Since spring 2026 the slop reports are practically gone. Our current challenge is much harder: high volume, high quality.

https://daniel.haxx.se/blog/2026/10/22/ignore-the-slop/

Linux maintainer is extremely unhappy with the high false positive rate from Mythos vuln: https://m.youtube.com/watch?v=NnV_cWeoo5Q&pp=0gcJCVgCo7VqN5t...

I think someone who likes AI thinks it’s good, someone who doesn’t, doesn’t think it’s anything impressive, and concretely nothing of any significance has happened to the world, certainly nothing like the crowdstrike shutdown so I don’t find the capabilities to be anything impressive.

> and concretely nothing of any significance has happened to the world

I would hypothesize that all the long-held "easily discovered if you look in the right place, but never reported and so never fixed" 0days in operating systems that criminal gangs and militaries have been relying on (to do cyberattacks with, unlock devices for forensic data recovery with, etc.), are increasingly being exposed and cleaned up, much faster than new such exploits can be discovered; and that this may have given an edge to whichever side of these conflicts don't rely so heavily on hacking the other to achieve their goals.

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It’s true that I’m an AI adopter. My psychosis is pretty advanced. I’m running four clankers in parallel right now.

The 9 bugs I got were clear security bugs under the Fil-C definition of memory safety. One reason why my experience could be an outlier is the effort I’ve gone to defining what the security properties of Fil-C are, to the point that there’s a crystal clear falsifiable boundary. So the bugs aren’t a matter of opinion or judgement. That helps clankers and it helps me when screening the bugs.

> concretely nothing of any significance has happened

This is a good point, but “cyber apocalypse dooming is an exaggeration” is a different statement than “bugs found by Anthropic aren’t real”. I agree that the dooming is an exaggeration. I don’t agree that Anthropic’s bugs suck.

Two reasons why bugs-found-by AI-are-really-scary and nothing-is-happening can be true at the same time:

1. Anthropic is sharing the bugs found by their most capable model with defenders, not attackers. Defenders are working overtime fixing those bugs before the embargo runs out.

2. The attackers that have access to Anthropic-class capability are using their bugs surgically. They aren’t using them so widely that folks would notice. That strategy is business as usual for advanced attackers

I obviously don't know if this applies for the Fil-C bugs but what we saw in Rust is that there's plenty of "technically that's not OK" which is very distant from "this will actually cause real world problems" https://forge-blog.github.io/posts/rust-std-memory-safety/

For example it's definitely not OK that you can impl Pattern in a way that causes non-UTF8 data in a string with safe code. But you probably didn't let random attackers impl Pattern, on a nightly Rust where that's even possible, and so that's not going to cause problems in our real world - even though it's wrong and must be fixed.

I'm speculating out on a limb here, but maybe the Mythos zero-days that were developed into working exploits involved a few of those "usually won't cause real-world problems" happenstances.

A model with all the world's knowledge might know exactly how to weave them together into a successful exploit. And if tomorrow's models are even more capable, perhaps what we're experiencing now is just a fire drill for what's coming.

Most of the bugs were things that fall into the “won’t cause real world problems” category.

But they were all things that unambiguously violated the Fil-C promise

> One reason why my experience could be an outlier is the effort I’ve gone to defining what the security properties of Fil-C are, to the point that there’s a crystal clear falsifiable boundary.

Building software boils down to defining things correctly. So, it sounds like you did most of the work here. Imagine that you took your definition and moved it into a formal specification (programming language) and then ran that to verify the security properties of your system. What's different?

Or, imagine that you took your original code as your specification language and then iterated on your understanding of it until it was correct. What's different?

Attention highlights and resolves bugs, so that's the baseline. In order for AI to get value, it has to be some kind of multiplier on your attention, but the reality is generally the opposite.

> Linux maintainer

I wonder what it's like maintaining a project where you regularly get competent contributions. No wonder they are less impressed with AI - they are the 0.1% of maintainers who had something better.

I see it the other way; Linux is a huge project, but being a solo maintainer for a mid-sized project like Fil-C is a different level than one of dozens of maintainers for a large project like Linux. Sort of like being a solo founder for a semi-successful startup is different than being a rank engineer at Google.
AI is a legitimate step change in every domain of knowledge work, cybersecurity included of course.

OP's post adopts a deliberately skeptical angle, it is a blog post for a company that advertises the ability to spot and patch vulnerabilities. They have an intrinsic motivation to minimize the believed effectiveness of wholesale SOTA-model cyber superiority which erodes their moat.

I have these things running 24/7 working on apks. They are extermely underwhelming, I spend most mornings annoyed looking at hallucinated/incomplete/insignificant findings from overnight.

Im about ready to stop using them overnight in this autonomous fashion. Its a great "intelligent" fuzzer but pretty mediocre when its steering the ship by itself.

I suspect the gap comes from whether or not you're being used for marketing/IPO bubble driving. I love Fil-C, and its still a small enough project that it doesn't make front page news if a problem with it is discovered. So I think the gap comes in in that they have no incentive to massively drum up the number of security vulnerabilities that they find, by publishing a huge number of false positives that then get quietly retracted

By contrast, when <tool> announces they've found XXXX vulnerabilities in Linux, it makes the news literally everywhere. Even if 0% of them turn out to be real, it doesn't matter - they've already gotten what they want out of it which is the round of coverage about how incredible <tool> is and its the end of the world

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You broke the site guidelines with this post. Can you please make your substantive points without swipes and avoid crossing into personal attack?

https://news.ycombinator.com/newsguidelines.html

Your response seems a bit overwrought, to call their claim nonsense solely because they used the word "representative" to describe their experience (and they did only say "probably representative"). They're not making a scientific claim, they're reporting an observation about 9 bug reports.