XBOW got a $250,000 Chrome bounty with AI agents in 6 days

XBOW, a startup in Seattle, says that Google gave $250,000 for an exploit. The exploit is a chain of 3 bugs in the Chrome browser. The team made it from August 2 to August 7 with AI agents. The agents used the GPT-5.6 Sol model of OpenAI. Google found the same bugs and made fixes. No person used the bugs against users of Chrome.

Who did what

The researchers set the targets, gave context, and examined the results of the agents. The agents looked in the source code of Chrome and wrote first drafts of the exploit code.

The 3 bugs

The chain lets attacker code operate on a Windows computer with no sandbox. The bugs are:

• A bug in the Maglev compiler gave read and write access in a memory cage.
• A bug in the animated WebP decoder let the exploit go out of the memory cage.
• Crashpad, the crash reporter, used a read that did not work as a correct result.

Time and cost

XBOW says that the API charges for the work were about $40,000. One of its researchers had 6 months of work on a bug of almost the same type with traditional methods. The team did it in 6 days.

The risk

XBOW says that the same speed can help an attacker who does not disclose the bugs. Google made fixes before a person used the bugs.