XBOW wins $250,000 Chrome bounty with exploit built by GPT-5.6 Sol agents in six days
Security firm XBOW said on 13 October that it won $250,000 from Google's Chrome bug bounty programme for a full exploit chain built with AI agents running OpenAI's GPT-5.6 Sol. The chain combined three previously unknown bugs — a V8 Maglev compiler flaw giving read/write inside the V8 sandbox, an animated WebP decoder flaw producing a single write outside it, and a Crashpad crash-handler bug that turned that write into full code execution — so that merely loading a web page could run code outside Chrome's sandbox on Windows, with no click or download. XBOW says its researchers and agents assembled the awarded chain between 2 and 7 August at a compute cost of about $40,000 based on its own usage logs, using a model anyone can access; Google has fixed all three flaws, and XBOW says they were never used against Chrome users. Google's Chrome 152 release notes credit XBOW researcher Brendan Dolan-Gavitt for the Crashpad flaw, CVE-2026-78952.
It shows a publicly available model plus human researchers producing a full browser exploit chain in days and at modest cost, narrowing defenders' window.