OpenAI-Powered Chrome Exploit Chain Earns $250,000 Bounty

Background

A browser exploit chain that used to take elite researchers months just came together in six days. The team used OpenAI's GPT-5.6 Sol model, working alongside human researchers, to find and exploit three previously unknown vulnerabilities in Google Chrome.

The Campaign

The campaign ran from August 2 to August 7, 2026, and was made public on October 13, 2026. XBOW made it public during the Black Hat and DEF CON security conferences in Las Vegas.

The Flaws

The chain stitched together three separate flaws: a bug in the Maglev compiler inside V8, Chrome's JavaScript engine; a flaw in an animated WebP image decoder, tracked as CVE-2026-85045; and a memory safety issue in Crashpad.

The Reward

Google confirmed the findings and paid the reward about a month after XBOW submitted them. The $250,000 figure is the top payout under revised Chrome Vulnerability Reward Program rules that Google announced in April 2026.

The Model

XBOW reported compute costs of around $40,000 in API fees for the six-day effort. The model involved, GPT-5.6 Sol, is publicly available – not a secret lab tool.

The Human Factor

Humans still in the loop, XBOW CEO Oege de Moor and researcher Brendan Dolan-Gavitt led the effort, directing AI agents through the campaign. This was the company's second attempt at a full-chain submission.

The Impact

Full-chain exploits of this kind traditionally took months. XBOW did it in under a week. The outcome here was the good version of events – the bugs went to the vendor, got patched, and got paid for.

The Future

If AI dramatically lowers the cost of producing these chains, submissions could become more frequent, testing how programs price their rewards and how quickly their triage teams can verify complex findings.