Reverse engineering Claude's CVE-2026-2796 exploit

Frontier Red Team reverse-engineered an exploit that Claude (Opus 4.6) authored for CVE-2026-2796, a Firefox WebAssembly JIT miscompilation: the bug allowed a call.bind wrapper to be unwrapped at instantiation, leading to type confusion and an unchecked path that enabled addrof/fakeobj primitives, WasmGC-based arbitrary 64-bit reads/writes, and ultimately code execution in a stripped js shell; the issue is now patched and the exploit relied on a testing environment with some mitigations disabled, but the case highlights improving LLM capabilities for writing exploits.