Top News

Anthropic's Mythos AI can chain bugs into exploits: Cloudflare
19 May 2026

Cloudflare has flagged a major security risk with Anthropic's Mythos AI model.

The tech giant found that the advanced system could link low-severity software vulnerabilities into more serious exploits.

This was discovered as part of Project Glasswing, where Cloudflare analyzed live code across its runtime, edge data path, protocol stack, control plane and open-source projects.

Mythos's unique ability to link vulnerabilities
Exploit creation

Unlike other large language models, Mythos could do more than just identify isolated bugs. It could also connect them into attack chains and generate proof-of-concept code to demonstrate whether a suspected flaw was exploitable.

This capability makes Mythos stand out in the field of software security, as attackers usually exploit multiple vulnerabilities together for unauthorized access or control.

Inconsistent refusals during legitimate vulnerability research
Model behavior

Mythos could also write code to trigger a suspected bug, compile it in a test environment and run the result. It could even revise its approach if the first attempt failed.

However, Cloudflare's findings raised questions about the consistency of model refusals during legitimate vulnerability research.

Sometimes, Mythos rejected requests to carry out security work but completed similar tasks when context changed, even without any change in code under review.

Over-reporting possible flaws by Mythos
Output quality

Mythos also generated a lot of noise that still required human review, especially in projects written in memory-unsafe languages like C and C++.

The model tended to over-report possible flaws, leaving security teams to differentiate between tentative findings and genuine vulnerabilities.

While Mythos improved output quality compared to earlier tools, it didn't eliminate the cost of triage.

Cloudflare's structured system around Mythos
Research strategy

Instead of a generic coding agent inspecting an entire repository, Cloudflare built a structured system around Mythos.

The approach starts with an investigation that maps a repository, identifies trust boundaries and attack surfaces, and generates tasks for later stages.

Then it runs multiple concurrent hunting agents, each focused on a specific attack class and software scope, before a separate validation agent tries to disprove the findings.

Improvements in coverage and quality of findings
Enhanced detection

Cloudflare's method improved both coverage and the quality of findings by narrowing Mythos's task and forcing independent review.

The company also used Mythos to adapt and refine this structured system.

The final tracing stage was deemed most important as it distinguishes a flaw in code from a vulnerability an attacker can actually reach, thereby improving accuracy in identifying potential security threats.