XBOW used AI agents on OpenAI's public GPT-5.6 Sol model to build a full Chrome-on-Windows exploit chain in six days for about US$40,000 of compute; Google paid its top US$250,000 full-chain reward — bugs already fixed in Chrome 152
On 13 October 2026 security firm XBOW published how it chained three then-unknown Google Chrome bugs into one attack that runs code on a Windows machine when a user only loads a web page, crossing both of Chrome's nested sandboxes. Researcher Brendan Dolan-Gavitt built the awarded chain between 2 and 7 August 2026 by directing AI agents running OpenAI's publicly available GPT-5.6 Sol model; XBOW puts the AI cost at about US$40,000 and says its first full chain earlier in the year took two months. The agents searched Chrome source, tested ideas, built working exploit pieces and drafted the exploit, while people chose targets, supplied context and decided which pieces to join. The stages were a V8 JavaScript-engine bug (CVE-2026-85045, fixed in 152.0.7977.82 on 3 Sep), an animated-WebP decoder bug used to escape the inner sandbox (no public identifier confirmed, fixed in the Chrome 152 cycle), and a Crashpad crash-handler bug (CVE-2026-78952, fixed in 152.0.7977.65 on 25 Aug). Google confirmed and fixed all three and paid US$250,000, its maximum full-chain reward under the 2026 Chrome VRP rules; XBOW says the bugs were never used against users. The point for defenders is speed: AI help cut the time to a browser full chain from months to days.
- Product
- Google Chrome on Windows (V8, animated-WebP decoder, Crashpad); OpenAI GPT-5.6 Sol used as the AI agent model
- Versions
- Fixed in Chrome 152.0.7977.65 (25 Aug 2026, CVE-2026-78952) and 152.0.7977.82 (3 Sep 2026, CVE-2026-85045); current Chrome 155 stable includes the fixes
- Exploited in Australia?
- unknown
- Patch to
- Nothing new to patch if Chrome is current; confirm managed fleets are at least on 152.0.7977.82 (now 155 stable) and that browsers have actually restarted. Treat the shrinking time-to-exploit as a reason to shorten browser patch windows and enforce relaunch.
Primary: XBOW — XBOW Built a Chrome Full-Chain Exploit Affecting a Billion Users in Six Days (13 Oct 2026) · Vendor: Google Chrome Releases — Stable channel update for desktop (Aug 2026, Chrome 152 fixes) · CVE: CVE-2026-85045, CVE-2026-78952 · The Hacker News — Researchers Used a Public OpenAI Model to Build a $250,000 Chrome Full-Chain Exploit in Six Days (14 Oct 2026)