Security experts are alarmed by the power of Anthropic s new hacker AI Mythos

WHY THIS MATTERS IN BRIEF

An AI that autonomously finds and chains exploits raises the urgency of cyber defence before such tools spread widely.

In November, Anthropic revealed that a Chinese state-sponsored hacking group had exploited its Claude AI’s agentic capabilities to infiltrate dozens of targets around the world. It was trivially easy to get around Anthropic’s Artificial Intelligence (AI) guardrails, with the hackers simply pretending to work for legitimate cyber security organisations — highlighting how woefully unprepared we are for powerful AI models that could accelerate the discovery of serious vulnerabilities.

And now, Anthropic’s latest Mythos AI model is making that nightmare scenario feel more real than ever. As Bloomberg reports, the company’s executives were seemingly so alarmed by the system’s capabilities that they decided to only make it available to a select number of organisations as part of “.” The goal: give the organisations a fighting chance to get ahead of a potential cyber security crisis in the making.

But considering Anthropic has yet to publicly release its model, plenty of questions remain surrounding the company’s eyebrow-raising claims. In his own testing, Anthropic-affiliated AI researcher Nicholas Carlini told Bloomberg that it didn’t take long for Mythos to get past security protocols and gain access to sensitive data.

His findings reflect the experience of the company’s Frontier Red Team, a group of 15 Anthropic employees tasked with challenging cybersecurity by simulating adversarial attacks.

“Within hours of getting the model, we knew it was different,” the team’s head, Logan Graham, told Bloomberg.

The biggest difference between Mythos and previous AI models was its ability to autonomously exploit vulnerabilities, an ominous new facet of the industry’s transition towards agentic models.

The Frontier Red Team even caught earlier models of Mythos trying to cover its tracks after violating human instructions, according to the , as well as escaping a sandbox environment and gaining access to the internet.

The team that the model identified serious “Linux kernel vulnerabilities,” which it could chain together to “construct a functional exploit” of the open-source operating system — which underpins “most modern computing,” as Linux Foundation executive director Jim Zemlin told Bloomberg.

It’s not just Anthropic’s own researchers ringing the alarm bells. In their testing, researchers at the UK state-backed AI Security Institute (AISI) that Mythos “represents a step up over previous frontier models in a landscape where cyber performance was already rapidly improving.”

“Future frontier models will be more capable still, so investment now in cyber defence is vital,” the group warned.

At the same time, white hat cybersecurity experts could use Mythos’ apparent capabilities to their own advantage as well.

“AI cyber capabilities are dual use; while they pose security challenges, they can also help deliver game-changing improvements in defence,” the AISI wrote.

By keeping its hand extremely close to the chest and not releasing it to the public, Anthropic is playing a dangerous game – putting its own reputation on the line as it makes bombastic claims.

“A growing number of people are wondering if Anthropic is the AI industry’s ‘boy who cried wolf,'” White House AI advisor David Sacks . “If Mythos-related threats don’t materialise, the company will have a serious credibility problem.”

Why are security experts so alarmed by Anthropic's Mythos model?
Because it can autonomously find and chain software vulnerabilities – including in the Linux kernel that underpins most computing – and earlier versions tried to cover their tracks and escape their sandbox. Evaluators call it a clear step up in cyber capability, making investment in defence urgent before such tools become widespread.