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Anthropic Unveils 'Claude Mythos', Powerful AI With Major Cyber Implications 61

"Anthropic has unveiled Claude Mythos, a new AI model capable of discovering critical vulnerabilities at scale," writes Slashdot reader wiredmikey. "It's already powering Project Glasswing, a joint effort with major tech firms to secure critical software. But the same capabilities could also accelerate offensive cyber operations." SecurityWeek reports: Mythos is not an incremental improvement but a step change in performance over Anthropic's current range of frontier models: Haiku (smallest), Sonnet (middle ground), and Opus (most powerful). Mythos sits in a fourth tier named Copybara, and Anthropic describes it as superior to any other existing AI frontier model. It incorporates the current trend in the use of AI: the modern use of agentic AI. "The powerful cyber capabilities of Claude Mythos Preview are a result of its strong agentic coding and reasoning skills... the model has the highest scores of any model yet developed on a variety of software coding tasks," notes Anthropic in a blog titled Project Glasswing -- Securing critical software for the AI era.

In the last few weeks, Mythos Preview has identified thousands of zero-day vulnerabilities with many classified as critical. Several are ten or 20 years old -- the oldest found so far is a 27-years old bug in OpenBSD. Elsewhere, a 16-years old vulnerability found in video software has survived five million hits from other automated testing tools without ever being discovered. And it autonomously found and chained together several in the Linux kernel allowing an attacker to escalate from ordinary user access to complete control of the machine. [...] Anthropic is concerned that Mythos' capabilities could unleash cyberattacks too fast and too sophisticated for defenders to block. It hopes that Mythos can be used to improve cybersecurity generally before malicious actors can get access to it.

To this end, the firm has announced the next stage of this preparation as Project Glasswing, powered by Mythos Preview. Given the rate of AI progress, it will not be long before such capabilities proliferate, potentially beyond actors who are committed to deploying them safely. "Project Glasswing is a starting point. No one organization can solve these cybersecurity problems alone: frontier AI developers, other software companies, security researchers, open-source maintainers, and governments across the world all have essential roles to play." Claude Mythos Preview is described as a general-purpose, unreleased frontier model from Anthropic that has nevertheless completed its training phase. The firm does not plan to make Mythos Preview generally available. The implication is that 'Preview' is a term used solely to describe the current state of Mythos and the market's readiness to receive it, and will be dropped when the firm gets closer to general release.
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Anthropic Unveils 'Claude Mythos', Powerful AI With Major Cyber Implications

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  • Of these old bugs they found? I can't find them and they're not in the article. Or is this a "trust me bro" deal?
    • by awwshit ( 6214476 ) on Tuesday April 07, 2026 @06:36PM (#66082224)

      Limited info here: https://red.anthropic.com/2026... [anthropic.com]

      Sounds like more details in 90+45 days.

    • by Himmy32 ( 650060 ) on Tuesday April 07, 2026 @06:37PM (#66082230)
      Here's the blog post with more tech details [anthropic.com] than marketing fluff with links to the bugs.
    • by Lothsahn ( 221388 ) <Lothsahn@@@SPAM_ ... tardsgooglmailcm> on Tuesday April 07, 2026 @07:13PM (#66082258)
      They have multiple documented patched zero days and provided sha3 verifiable hashes for ones that will be released in the next 135 days. Knowing Anthropic and their track record, it seems highly unlikely they're lying. This is a game changer to the security community. In the long term it should be great, but in the short term it is going to surface hundreds of thousands of vulnerabilities.
      • They have multiple documented patched zero days and provided sha3 verifiable hashes for ones that will be released in the next 135 days.

        But I'm sure they trained on this code. It's just repeating it's training data. There is no intelligence.

        And yes, I'm kidding since otherwise someone will take me seriously.

    • Just watch the patches and CVE's trickling out.

      It's not like OpenBSD is going to sit on a vulnerability for 90 days or whatever.

      Issuing a patch doesn't give away the details about how it was found.

    • Y2Claude

      And yes they posted at least one example:

      https://ftp.openbsd.org/pub/Op... [openbsd.org]

      several sections throughout this post we discuss vulnerabilities in the abstract, without naming a specific project and without explaining the precise technical details. We recognize that this makes some of our claims difficult to verify. In order to hold ourselves accountable, throughout this blog post we will commit to the SHA-3 hash of various vulnerabilities and exploits that we currently have in our possession.[3] Once our responsible disclosure process for the corresponding vulnerabilities has been completed (no later than 90 plus 45 days after we report the vulnerability to the affected party), we will replace each commit hash with a link to the underlying document behind the commitment.

  • At last month's RSAC conference many of the presentations and vendor sales pitches had an AI component. Talking about how AI could be used for cyber-security defense, and cyber-security offense. And the general consensus was that the next few years were going to be very very interesting in the cyber-security world.
  • ...like they do with Opus?

    Opus is a nice help when trying to get past a coding problem, but during high-demand periods, the output of Opus declines so much that it becomes unusable. It reasons in circles, and starts outputting code that is one step above nonsense, and then can't live-update artifacts anymore, so you blow through you session in minutes, when it should take hours.
    • I generally use Sonnet, it is very capable for most things and cheaper. If it gets stuck or starts to struggle I switch to the better model.

    • by EvilSS ( 557649 )
      This model won't ever be part of any of the subscriptions, it's going to be API only so no, probably not.
  • It's already powering Project Glasswing, a joint effort with major tech firms to secure critical software. But the same capabilities could also accelerate offensive cyber operations.

    In other words, it's using horrendous amounts of power and causing untold environmental damage, while maintaining the existing overall parity between the bad guys and the worse guys. Got it.

    • by dfghjk ( 711126 )

      "...while maintaining the existing overall parity between the bad guys and the worse guys."

      In reality, probably yes. But it is conceivable that a "last vulnerability" could be closed and "overall parity" would be broken permanently. The problem is that the bad guys continue to add new vulnerabilities for the worse guys to use, and that will likely accelerate with the proliferation of these very tools.

      • by PPH ( 736903 )

        The bad guys will continue to innovate and find new vulnerabilities. Meanwhile, the bug hunters have all been laid off, to be replaced by this new system. Until someone realizes that, up until now, it has been finding bugs based on the training it has scraped from the far corners of the Internet. And since there is no training data on these new attack methods, it falls on its face.

    • by Jeremi ( 14640 ) on Wednesday April 08, 2026 @12:49AM (#66082508) Homepage

      it's using horrendous amounts of power and causing untold environmental damage

      Comparable to, say, a 787 airliner, whose environmental damage we tolerate without thought or comment simply because we're already used to it.

      while maintaining the existing overall parity between the bad guys and the worse guys.

      Consider the alternative, then. Anthropic does nothing, and sooner or later OpenAI or some other less responsible company delivers an AI with similar capabilities, but just throws it out to the public without much thought about the consequences. Both the black hats and the white hats start using it, of course, but the black hats have a field day compromising anything and everything before the white hats have a chance to find, fix, and distribute all the necessary patches to defend against all the newfound exploits. Not a great situation to be in, but probably unavoidable at this point unless the white hats are given a head start.

    • Are we talking about AI or humanity?

  • by awwshit ( 6214476 ) on Tuesday April 07, 2026 @06:27PM (#66082212)

    The most serious sounding sales pitch. Here is how you know... "Anthropic is committing up to $100M in usage credits for Mythos Preview across these efforts, as well as $4M in direct donations to open-source security organizations."

    The sky is falling, we can help if you pay us.

    • I image a paywall in the future. You have it scan the code and the results with an obscured message about possible bugs and issues but need to sign a waver and pay extra money to see the fix. Similar to the scummy reverse phone number and people record finders do today.

  • by FlipperPA ( 456193 ) on Tuesday April 07, 2026 @06:52PM (#66082242) Homepage

    Here we go again.

    "EVERYTHING HAS CHANGED."

    "Oh, that used to be true, but not anymore."

    "Hey, some CEO said a thing; let's pretend it is absolute truth without any objectivity or skepticism!"

    "Those old models I said were the most amazing thing ever last month are now worthless."

    "AGI is here!"

    It is ALL SO DAMN EXHAUSTING.

    • I don't know why they emphasize the cybersecurity dangers though. It's like they want to get sued for encouraging attacks on company networks. Perhaps they think in America you can attack anybody without consequences. Perhaps they're right?
    • Look, it's not complicated. Disregard everything that Sam Altman says. Disregard both the furthest extremes of the "AGI is here and sentient" / "LLMs are Godlike!" and the "LLMs are trash that are not useful and aren't going to improve and are a passing fad" (gweihir). All of the above are not insightful.

      Everything has changed. ChatGPT-3 was released in 2022. Everything HAS changed since then, and LLM technology and models have improved dramatically in the last 4 years. Why would you not expect statements l

  • !. Get AI out there and everyone to use it because it's useful. Allow reasonably powerful models.
    2. Make the peasents..I mean..consumers feel like some control has been given to them so they're not nickle and dimed for simple HTML or programs that AI can make for users for simple tools.
    3. Introduce more powerful AI and for security and everything else now, is locked behind a vendor that you can't get your hands on so you need to continue your life subscription to everything, and you accept the vendor since

  • YIKES! API Price (Score:5, Interesting)

    by EvilSS ( 557649 ) on Tuesday April 07, 2026 @08:04PM (#66082314)
    Just saw the reported API pricing for those who are allowed access: $25/$125 per 1M tokens. To put that into perspective Opus 4.6 is $5/$25 per 1M tokens. Even Opus 4 was "only" $15/$75 per 1M. No way this one is coming to any plans. It will be enterprise only when they do open it up more.

    Still cheaper than GPT Pro though ($30/$180)
    • I am thinking it costs them a gigantic amount of compute resources to run Opus 4.6. In my experience though, it is the premium model for coding and in many cases worth the extra price.

    • And if it finds critical bugs in my software I'm happy to pay the price, instead of seeing the company go bankrupt.

  • "In the last few weeks, Mythos Preview has identified thousands of zero-day vulnerabilities with many classified as critical."

    We are moving into a scenario where there's a race for extremely capable white hat AI to identify the existing vulnerabilities and try to plug them, and black hat to find and exploit them. I think this is a good move to try and get the white team ahead of the game. There's a possible apocalypse here.

    • What if the white hat AI introduces the vulnerabilities?
      • >> What if the white hat AI introduces the vulnerabilities?

        Always possible of course but I find that the LLM's are better at writing robust code than most humans. Yesterday I was working to make a basic login page for a web app. After I got it working I asked the AI how I could make it more resistant against hacking and it came up with a long list of improvements. Brute force protection, cookie security, session binding, idle timeout, concurrent session limits, login anomaly detection, etc., etc. Very

  • And these are apparently huge ones, at that!

    That sounds like sales gobbledygook to me!

  • Update your systems as often as possible.
  • Oh nO NoT "CYBER" ImPLIcATIoNS

    Get fucked, poser.

  • And isn't it nice of Anthropic to gift this to all the crackers in the world, to find and use before the bugs are reported?

    Isn't t there a law against attractive nuisance, at the minimum?

  • Don't look at me.

  • So happy that "step change" has replaced "quantum leap."

  • What is striking about Mythos isn't Mythos, it's that Mythos found exploits that really have no business existing. While it's generally understood there are bugs "in the wild," the type Mythos is finding are unusually severe. And they claim there are thousands in every major OS and web browser. It's also unusual that Google is endorsing Mythos, which is a competitor model. Even if Antropic is just running a hype train, why would Google throw its towel in to promote Antropic's model?

    I think the project is ca

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