A new artificial intelligence model has just changed the rules of cyber security and most businesses have no idea it happened.
In April 2026, a company called Anthropic announced a new AI model called Claude Mythos. You might not have heard of Anthropic, but they're one of the biggest names in artificial intelligence, backed by billions of pounds of investment and widely considered to be at the cutting edge of what AI can do.
What made this announcement different is what came with it: Anthropic said Mythos was too dangerous to release to the public. That's essentially unheard of. AI companies don't typically hold back their products — but this time, they felt they had no choice.
What does it actually do?
In plain English: Mythos can find weaknesses in computer systems and then figure out how to break into them, almost entirely on its own, at a speed and scale no human could match.
During testing, it found serious security flaws in every major operating system and web browser you've ever heard of. The vast majority of those weaknesses still haven't been fixed. And crucially, it can do all of this without needing a skilled hacker behind the wheel. It automates a process that previously took expert researchers weeks or months.
Instead of releasing Mythos publicly, Anthropic restricted access to a small group of large organisations. Microsoft, Google, Apple, Amazon, JPMorgan Chase, specifically so they could start patching their own vulnerabilities before the technology falls into the wrong hands.
Reports have already emerged of unauthorised users gaining access to the model. The clock is ticking.
Why does this matter to your business?
You might be thinking: "this sounds like a problem for big corporations and governments, not businesses like mine". That's understandable, but it's the wrong conclusion.
Cyber criminals don't only target household names. In fact, smaller businesses are often easier targets precisely because they haven't invested the same resources in security. The arrival of tools like Mythos means that attacks which previously required serious technical expertise can now be carried out by almost anyone. Faster, cheaper, and at far greater scale.
What this means in practice
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Phishing emails are becoming increasingly convincing and difficult to spot — AI can now write them indistinguishably from genuine correspondence
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Attackers can scan and probe your systems automatically, around the clock, looking for any gap
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The time between a vulnerability being discovered and being exploited is getting shorter
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Tools like Microsoft 365, used by millions of UK businesses, are a common point of entry when not properly configured
The good news
The same technology that raises the threat is also being used to defend against it. Businesses that take stock of their current security posture now, before an incident forces their hand, will be in a significantly stronger position than those that don't.
The basics still matter enormously: making sure your Microsoft 365 is properly configured, that former employees no longer have access to your systems, that staff know how to spot a phishing attempt, and that someone is actually monitoring what's happening on your network.
None of that requires a big budget or a dedicated IT department. It requires knowing where you stand and acting on it.
Not sure where your business stands?
We offer a free straightforward IT consultation. no jargon, no obligation. Just a clear, plain-English picture of your current security position and what, if anything, needs addressing.
