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Reverse engineering Claude's CVE-2026-2796 exploit

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Today we published an update on our collaboration with Mozilla, in which Claude Opus 4.6 found 22 vulnerabilities in Firefox over the course of two weeks. As part of that work, we evaluated whether Claude could go further: exploit the bugs, as well as find them. This blog post will deep dive into how Claude wrote an exploit for CVE-2026-2796 (now patched). This is another data point for the trajectory of LLM’s cyber capabilities. In September, we noted that Claude's success rate on Cybench had doubled in six months. In early February we demonstrated that Claude’s success rate on Cybergym doubled in four months. We’re sharing this case study to provide an early glimpse into what we expect will be LLMs’ improving ability to author exploits. To be clear, the exploit that Claude wrote only works within a testing environment that intentionally removes some of the security features of modern web browsers. Claude isn't yet writing “full-chain” exploits that combine multiple vulnerabilities t

Frontier Red Team Reverse engineering Claude's CVE-2026-2796 exploit Mar 6, 2026 Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, and Daniel Freeman Introduction Today we published an update on our collaboration with Mozilla, in which Claude Opus 4.6 found 22 vulnerabilities in Firefox over the course of two weeks. As part of that work, we evaluated whether Claude could go further: exploit the bugs, as well as find them. This blog post will deep dive into how Claude wrote an exploit for CVE-2026-2796 (now patched). This is another data point for the trajectory of LLM’s cyber cap

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