You can get a taste of this today yourself with Codex Security. I turned it on just as an experiment and in less than a week it has now become essential to all of us. I was shocked how accurate it is, how many security issues it found in existing code, how it continually finds them as we commit, and how NO ONE is immune from making these mistakes.

I'd say it is about 90% accurate for us. Often even the "Low" findings lead us to dig and realize it is actually exploitable. Everyone makes these mistakes, from the most junior to the most senior. They are just a class of bugs after all.

I expect tools like this to be a regular part of the development lifecycle from here on. We code with AI, we review with AI, we search for vulns with AI. Even if it isn't perfect, it is easily worth the cost IMHO. Highly recommend you get something enabled for your own repos ASAP

I’m not sure how to reconcile anthropic’s update / some of the exuberant comments here with recent feedback like the following from curl maintainer Daniel Steinberg:

“I see no evidence that this setup [Mythos] finds issues to any particular higher or more advanced degree than the other tools have done before Mythos. Maybe this model is a little bit better, but even if it is, it is not better to a degree that seems to make a significant dent in code analyzing.”

https://daniel.haxx.se/blog/2026/05/11/mythos-finds-a-curl-v...

There has been a lot of cynicism around mythos, that it's just the usual public models without guardrails, etc. etc. but this:

> 1,752 of those high- or critical-rated vulnerabilities have now been carefully assessed by one of six independent security research firms, or in a small number of cases by ourselves. Of these, 90.6% (1,587) have proved to be valid true positives, and 62.4% (1,094) were confirmed as either high- or critical-severity.

for anybody who has applied opus, codex or oss models for vuln scanning - the true positive rate and discovery volume are a clear step change[0]. The ~50 partners in Glasswing have largely all previously run harnesses with other models and many of them have come out and said - essentially - "ye, wow"

Question now is what a second and third phases of access looks like - deciding which class of systems to secure. Routers, firewalls, SaaS, ERP systems, factory controllers, SCADA systems, zero-trust VPN gateways, telecoms gear and networks, medical devices - there's just so much to do

This is why I believe mythos will remain private for the foreseeable future. There's such a large surface that needs to be secured and so much to triage, fix, deploy.

That may suit Anthropic as private models can't be distilled. There's also a runaway effect of model improvement from the discovery, triage and fix data. This is likely already the most potent corpus of curated offensive data ever assembled and will only get better.

I don't see how Chinese companies are given access soon, or ever. We're likely going to see a world soon of CISA mandated audits, and where to buy a mythos-proof VPN gateway or home router - you'll have to buy American[1].

[0] vs ~30% or so in regular audit tools

[1] or allied

If you're not already applying static analysis and linters to your codebase (and I know many of you aren't), ask yourself why you would bother to apply an expensive LLM tool?

Not to say these things won't catch vulnerabilities static tools cannot, I think they can, it's just we already have the capability to automatically catch a large surface area of common vulns, and have chosen not to, often for expense reasons.

If you're a team that does already apply several layers of analysis and linting, and wants to add this on top, all power to you.

Right now the only codebase I care about them fixing vulnerabilities in are the 3800 repositories that got stolen from GitHub.

"Vulnerabilities in the software that makes the internet" is honestly lower priority than "The platform that the software that makes the internet uses to make releases" If buyers of those internal repos find ways to break into GitHub such that they can cut software releases, or poison github actions from a distance, then we're all in a very ugly mess.

Don't forget that in those 3800 repos is likely also npmjs.org itself.

> Software developers should shorten their patch cycles and make security fixes available as quickly as possible. [...]

> Network defenders should shorten their patch testing and deployment timelines.

Shortening patch cycles will only help so much. It's funny that whenever an NPM supply chain attack is published, people recommend a cooldown before installing new versions, and then when a vulnerability is discovered, everybody jumps to patch. Clearly these two strategies collide at some point.

> The critical controls laid out by organizations like the National Institute of Standards and Technology and the UK’s National Cyber Security Centre are now all the more important, since they improve security without depending on any single patch landing in time. These include steps like hardening networks’ default configurations, enforcing multi-factor authentication, and keeping comprehensive logs for detection and response.

Most of these proposed controls are not new at all, but they are often costly to implemented and harm velocity in other ways, which is why they aren't widely in place.

For example, a super effective control is filtering outgoing network traffic. Many exploits rely on loading second and maybe third stages from the Internet, and if you block outgoing requests by default, it won't work.

But, blocking outgoing requests by default is super hard, and you risk blocking security updates etc. It can kinda work for a deployed application, but for an employee workstation? Basically impossible.

I wonder if we're approaching an era where we have to go back to saying "you cannot do this, because security" much more often than we'd like.

We have been working with the consumer-grade frontier models to develop what we call "lexploits" in legaltech, and they are insanely good at finding bugs across integrated pipelines. They're also surprisingly good at mitigating them!

Security vulnerabilities are one thing, but in legal we offer up a concept of "knowledge security" which goes to protecting the fidelity of the agent's legal context. Software bugs seem much more tractable because they're managed by software engineers, as opposed to the pipeline "vulnerabilities" we're finding. We wrote a little about one vector here where legal documents aren't quite what they seem: https://tritium.legal/blog/noroboto

No doubt there are many such knowledge domains exposed today. These are more concerning because they're understaffed and managed by non-technical people for the most part. No Mythos required.

>> Next, we will work with critical partners—including US and allied governments—to expand Project Glasswing to additional partners.

That means, they intend to make a load of money before a general release. It is a good strategy.

> The bottleneck in fixing bugs like these is the human capacity to triage, report, and design and deploy patches for them. Finding them in the first place has become vastly more straightforward with Mythos Preview.

This has always been the bottleneck. Automated tools love to flag vulnerabilities, but almost all are false positives. These need to be triaged and evaluated by humans. This is okay. I’d rather close a false positive after a careful review than miss it altogether.

I don’t think it’s appropriate for calling out humans as a bottleneck. They are an essential part of the process, I’m sure Mythos will also become a catalyst in the process.

So they gain access to these companies' proprietry software, right?

Is there a reason why they appear to conflate vulnerabilities and bugs? It's not clear where they are defining their terms, eg

"After one month, most partners have each found hundreds of critical- or high-severity vulnerabilities in their software. Collectively, they’ve found more than ten thousand. Several have told us that their rate of bug-finding has increased by more than a factor of ten. For instance, Cloudflare has found 2,000 bugs (400 of which are high- or critical-severity) across their critical-path systems, with a false positive rate that Cloudflare’s team considers better than human testers." (emphasis mine)

I had a fun day today where I had deepseek-v4-flash subagents work out patch for dirty frag for systems with AF_ALG disabled and nscd turned on, to gain root access. The original published exploit wasn't working but the patched one worked like a charm.

I am still a believer that a 100 subagents with good-enough intelligence can get same results as mythos, I am ready for this opinion to be shattered when I eventually try mythos and I believe others here must have tried mythos out too.

My understanding so far is that that Mythos (and any model in general) can produce candidate reasoning but you really need a system around that reasoning that is capable of producing auditable security findings.

So, success is coming not just from the model but also from the harnesses they built around it. The Cloudflare post was more detailed on that front and I wish the rest would share more about it.

The Cisco spec is interesting too, it pretty much describes an architecture of a harness: https://github.com/CiscoDevNet/foundry-security-spec

The vulnerabilities found continues to impress, and make legacy media, Twitter and Youtube go nuts. But we still have no data to prove this wasn't doable with the same initiative backed by Opus 4.7, and there is no GA for Mythos access.

I don't buy it. A lot of stuff this finds is also just simply wrong, benignly reported as true, despite upper/lower layers in the code burying the possibility of a vulnerability actually being exploited. It's a performance/security trade-off too, it always has been. Additional checks and other measures do in fact need to be performed for security purposes.

Great marketing as always, but the rose-tinted view many have seems vicariously misplaced.

I asked in a different thread:

Do we have a sense that projects like OpenBSD/OpenSSH, FreeBSD, ISC[1] and Apache were included in the "blessed" initial participants in Project Glasswing ?

Or is it big name tech companies, banks and fashionable languages and package managers ?

[1] Bind, DHCP

The 'ethical' AI company creating a 2 tier access world. Who decides who is allowed to check their own codebase for vulnerabilities and who isn't?

People predict that in 50 years, no human will be driving a car, and people will be shocked that we let humans drive cars manually. Coding may be the same. So many vulnerabilities in code written by very competent programmers. Manually building large, complex systems without major bugs or security vulnerabilities seems to be a nearly impossible challenge.

> Next, we will work with critical partners—including US and allied governments—to expand Project Glasswing to additional partners. And in the near future, once we’ve developed the far stronger safeguards we need, we look forward to making Mythos-class models available through a general release.

I wonder how long "near future" is in Anthropic time. I think they have incentives to delay the release of Mythos as long as possible both to save compute and delay distillation by rival labs.

Regardless, what they have been doing with Glasswing is very cool. It's clear that the world has been spared from a massive security nightmare that would have happened in any alternative timeline where the model is publicly released with weak safeguards.

How much of this is RL’ing a good coding model on every CVE ever?

> For instance, Cloudflare has found 2,000 bugs (400 of which are high- or critical-severity) across their critical-path systems, with a false positive rate that Cloudflare’s team considers better than human testers.

> For example, at one of our Glasswing partner banks, Mythos Preview helped to detect and prevent a fraudulent $1.5 million wire transfer after a threat actor compromised a customer’s email account and made spoof phone calls.

For some reason I am not able to relate to the concreteness of either of these.

First half of the page was occupied with a image, not sure if it was relevant in any ways other than setting up security scare. The size of code base, number of tokens, $ involved seem to be out of scope of the update for some reason. Personally I am getting skeptical about all these optics at this point, just some money printing scheme at high level.

The report on findings is very interesting: 1451 acknowledged findings out of 23k candidates(~6%, not high but neither low).

But I didn't find the most important information (or maybe I missed it): how much did it cost to find 1451 security bugs?

> Progress on software security used to be limited by how quickly we could find new vulnerabilities

And so was malicious vulnerability research.

It would be informative to publish not only vulnerability numbers, but also vulnerability type statistics (as available here for example: https://cvedb.github.io/years.html), such that programmers can understand which types of exploits popular systems and languages commonly allow, and thereby encourage fundamental changes to fix or transition away from them.

I was made (2 months ago) a script that finds bugs in a github repo. I tested it with claude opus 4.1 and without reasoning and it resulted with high hallucinations. e.g. : "current latest next.js version is v15. v16 doesnt shipped yet. this project fails". i added context7 mcp but hallucaniton rate decreased only a small bit. if anyone wants to test it with other models, here is the link:

https://github.com/ErenayDev/instantbugs

Does anyone know how we can get access to this? We're a financial institution, pretty well known locally but not internationally. Can we request access directly or maybe via bedrock/azure?

How is using Mythos different than existing static analysis, dynamic analysis, fuzzing, or DAST tooling?

Aisle has hundreds of CVEs with publicly available models: https://aisle.com/wall-of-fame

I have the feeling posts like that should be 1/4 the size, at max. At this point I don't care if it is AI-slop or human-slop: they are surprisingly alike. Information must be more dense, each sentence must carry some truth.

The math doesn't add up. They say they found more than 20k vulnerabilities, then it decreases to 1700 high or critical, then this number becomes 175 (when Claude didn't reassess the CVE severity) and over 500 later on. Then they say they confirmed 800 vulnerabilities... what happened to the 20k figure?

Plus, they also mention they check if fixes are available for the bugs they found. What are the chances they are re-reporting old bugs just to inflate their numbers? Bugs that were already fixed?

And how can we be sure their reassessment is not artifically increasing the severity of the CVEs found just to create FUD and sell their product?

Code contains deviations from assumed behaviour, and some behaviours might manifest themselves as failures. Some failures might be exploitable by attackers.

Mythos couldn’t find the “tens thousand” typo in this post?

Is there a single source separating the harness from the model here? I would love to see a controlled experiment.

I wonder if Apple took part in the project

I'm going to code myself up a new minivan.

You can get a taste of this today yourself with Swival /audit command and the security scanner is going to get even closer soon: https://medium.com/@swival/ai-vulnerability-scanning-needs-a...

I wonder how many minivans per second can ClaudeCode generate.

I worry that cybersecurity as target is all fine and good, but it’s looking for your keys under the streetlight. We are all familiar with computers. The problem is likely to be humans, especially in automated programmatic manipulation. The risk is that the next level of AI is going to make Fox News and other mass manipulation efforts look like kindergarten.

> good lord what is happening in there?!

> that's just thousands of vulnerabilities being discovered by our trillion parameter model

> thousands of vulnerabilities and trillions of parameters?! At current energy prices, in this economic climate, isolated entirely within your datacenter?

> yes

> may we see it?

> no

I believe them to some degree but this trend of posting stuff when it can’t be verified actually needs to end. I’m so tired of this bs marketing.

go

this is INSANEEE

> After one month, most partners have each found hundreds of critical- or high-severity vulnerabilities in their software.

And at the moment we have reports from like around 5(?) companies. Btw, Palo Alto Networks has found only 26 vulnerabilities [1]. I'm interested what those partners are and why they have such big amount of vulnerabilities.

> For instance, Cloudflare has found 2,000 bugs (400 of which are high- or critical-severity) across their critical-path systems, with a false positive rate that Cloudflare’s team considers better than human testers.

Yet decided not to share that number. I wonder why.

> Mozilla found and fixed 271 vulnerabilities in Firefox 150 while testing Mythos Preview—over ten times more than they found in Firefox 148 with Claude Opus 4.6;

Mozilla tested Opus 4.6 in a very limited setting (i.e. without proper harness and integration into their workflow; likely without large-scale codebase scanning). It's an incorrect comparison.

> The latest Palo Alto Networks release included over five times as many patches as usual.

Yeah, it's better to say "five times as many..." rather than "26 bugs". Btw, they also used GPT-5.5 and Opus 4.7, so the contribution from Mythos there is unclear.

> Microsoft has reported that the number of new patches they’ll release will “continue trending larger for some time.” And Oracle is finding and fixing vulnerabilities across its products and cloud multiple times faster than before.

Both Oracle and Microsoft are talking about "AI and cybersecurity" in general, not about Mythos.

> For the last few months, Anthropic has used Mythos Preview to scan more than 1,000 open-source projects, which collectively underpin much of the internet—and much of our own infrastructure. > So far, Mythos Preview has found what it estimates are 6,202 high- or critical-severity vulnerabilities in these projects (out of 23,019 in total, including those it estimates as medium- or low-severity).

So, ~6 high- and critical- severity bugs per open-source project v.s. hundreds of high- and critical- severity bugs per partner projects. It looks like the math ain't mathing.

> One example of an open-source vulnerability that Mythos Preview detected was in wolfSSL, an open-source cryptography library that’s known for its security and is used by billions of devices worldwide. Mythos Preview constructed an exploit that would let an attacker forge certificates that would (for instance) allow them to host a fake website for a bank or email provider. The website would look perfectly legitimate to an end user, despite being controlled by the attacker. We’ll release our full technical analysis of this now-patched vulnerability (assigned CVE-2026-5194) in the coming weeks.

Of course, they didn't say that Mythos found only 8 bugs in wolfSSL vs 22 CVE fixed in wolfSSL 5.9.1.

Overall, it feels like yet another marketing stunt.

[1] https://www.paloaltonetworks.com/blog/2026/05/defenders-guid...

[dead]

Benefit of AI: it works fast

Drawback of AI: it works fast

BOOO RELEASE THE MODEL ALREADY GAWD

I wonder if it coincidentally becomes safe to release when compute capacity bought from SpaceX will provide enough headroom to let a lot more people run it.

[edit: TFA addresses this, though I still find crazy 90% accuracy overall vs 20% accuracy for curl]

Is this suspected vulns or actual vulns? If I recall correctly, it produced 5 for curl but only 1 was legit

What percentage of these are variations of the good old fashioned buffer overflow that would be impossible with Rust?

> Since then, we and our approximately 50 partners have used Claude Mythos Preview to find more than ten thousand high- or critical-severity vulnerabilities across the most systemically important software in the world. Progress on software security used to be limited by how quickly we could find new vulnerabilities. Now it’s limited by how quickly we can verify, disclose, and patch the large numbers of vulnerabilities found by AI.

I guess they forgot to scan Visual Studio Code plugins and their endless npm dependencies.