Researchers Used a Public OpenAI Model to Build a $250,000 Chrome Full-Chain Exploit in Six Days

Security firm XBOW chained three then-unknown Google Chrome bugs into an attack that runs code on a Windows computer when a user loads a web page. Its researchers built the chain in six days by directing AI agents running OpenAI's GPT-5.6 Sol. The agents searched Chrome's source code, tested ideas, built proofs of concept and wrote first drafts of the exploit, while the researchers chose targets, supplied context, challenged results and decided which pieces to join. Google confirmed and fixed all three bugs and paid XBOW its top $250,000 reward.

Export STIX 2.1 Export JSON Request a correction (GitHub issue)

Timeline

2026-01 XBOW set the Chrome full-chain challenge at a staff meeting in Malta. · The Hacker News

2026-08-02 The six-day sprint to build the awarded chain began during Black Hat and DEF CON week. · The Hacker News

2026-08-07 The sprint ended with the awarded chain built; one earlier version had nearly failed because a bug it relied on was already known to Google, so XBOW swapped that part. · The Hacker News

2026-08-25 Google fixed the Crashpad bug in Chrome 152.0.7977.65. · The Hacker News

2026-09-03 Google fixed the V8 bug in Chrome 152.0.7977.82. · The Hacker News

Sources · 1

Researchers Used a Public OpenAI Model to Build a $250,000 Chrome Full-Chain Exploit in Six Days — The Hacker News, 2026-10-14

Links re-checked 2026-10-26 by the weekly refresh. A link that moved or stopped answering is flagged above; it is not a change to the record.

At a glance · as reported

Window	August 2-7, 2026
Attacker	XBOW researchers directing AI agents running OpenAI's GPT-5.6 Sol (a disclosed security research effort)
Scale	Three chained bugs; six-day build; about $40,000 in AI charges; $250,000 reward; an estimated 1 billion Chrome-on-Windows users at risk before the fixes, according to XBOW
Impact	The chain crossed both of Chrome's nested sandboxes and gave code execution outside Chrome on Windows with no user click or download. XBOW says the bugs were never used against Chrome users and all three are now fixed.
Defender	Google Chrome (Chrome Vulnerability Reward Program), with Chrome users on Windows as the potentially exposed population
Response	Google confirmed all three bugs, fixed them in Chrome 152.0.7977.65 (Aug 25) and 152.0.7977.82 (Sep 3), and paid XBOW its top $250,000 full-chain reward. Users are advised to relaunch Chrome and confirm version 152.0.7977.82 or later.

Tactics (MITRE ATT&CK)

TA0001 Initial Access
TA0002 Execution
TA0004 Privilege Escalation
TA0042 Resource Development

Mapped by the maintainer from the reports.

Models and agents named

GPT-5.6 Sol — attacker

Published by the weekly machine review (claude-sonnet-5-5 (automated review)) from the sources above on 2026-10-25: every field is as the sources state it, or empty. Compiled from the public sources above, as reported. Not an attribution, a finding of fault or a legal conclusion; figures are those stated by the sources. One event, as of its sources' dates.