A team at security firm **XBOW** has successfully chained three then-unknown **Google Chrome** bugs into a single, potent attack. This exploit allowed for arbitrary code execution on a **Windows** computer merely by loading a malicious web page, requiring no user interaction like clicks or downloads. ### AI Accelerates Exploit Development Remarkably, **XBOW** researchers built this full-chain exploit in a mere six days, primarily by directing AI agents running **OpenAI**'s publicly available **GPT-5.6 Sol** model. **Google** has since confirmed and patched all three vulnerabilities, awarding **XBOW** its maximum $250,000 reward for a complete Chrome exploit.  ### Bypassing Chrome's Sandboxes **Chrome** employs two nested sandboxes to isolate web page code and prevent unauthorized access to the underlying system. The **XBOW** exploit successfully bypassed both, achieving code execution outside of **Chrome** on **Windows**. All three bugs are now fixed, and **XBOW** has stated there is no evidence of them being exploited in the wild. The two publicly identified vulnerabilities were addressed in **Chrome 152.0.7977.65** on August 25 and **152.0.7977.82** on September 3. Users are advised to restart their browser to ensure the update is applied and confirm their version is **152.0.7977.82** or later. ### The Six-Day Sprint The rapid development occurred between August 2 and August 7, coinciding with the **Black Hat** and **DEF CON** conferences. This sprint, however, followed months of prior foundational work. **XBOW** highlighted that the six-day run incurred approximately $40,000 in AI charges. **XBOW** clarified the division of labor between AI and human researchers. The AI agents were instrumental in searching **Chrome**'s source code, generating proof-of-concept code, and drafting exploits. Human researchers provided context, selected targets, validated AI outputs, and integrated the various components. Brendan Dolan-Gavitt, the researcher who spearheaded this particular chain with the AI agents, noted the significant shift: "Pre-LLMs a Chrome full chain would take a team of four around 6-9 months to be produced, our first submission took 2 months. The awarded one? six days." ### The Vulnerabilities Unpacked The three chained bugs each resided in distinct components of **Chrome**. **Google**'s release notes credit Dolan-Gavitt of **XBOW** for two of them. | Stage | Where | CVE | Fixed in | |---|---|---|---| | 1 | **V8**, Chrome's JavaScript engine | **CVE-2026-85045** | 152.0.7977.82 (Sep 3) | | 2 | Animated-**WebP** image decoder | No public identifier listed | Chrome 152 cycle | | 3 | **Crashpad**, Chrome's crash handler | **CVE-2026-78952** | 152.0.7977.65 (Aug 25) | * The first bug, **CVE-2026-85045** in **V8**, Chrome's JavaScript engine, provided memory control to the attacker. * The second, found in the animated **WebP** image decoder, leveraged this control to escape the inner sandbox and perform a precise memory write. * The third, **CVE-2026-78952** in **Crashpad**, Chrome's crash handler (which operates outside the sandbox), escalated that single write into full code execution on the machine. Both identified bugs are rated high severity and require the user to load a malicious page. The **WebP** bug was also fixed within the **Chrome 152** cycle, though its specific public identifier could not be confirmed in the provided information. ### Setting a New Precedent **Google**'s **Chrome Vulnerability Reward Program**, updated in 2026, offers up to $250,000 for a full-chain exploit. **XBOW**'s achievement marks the first full-chain **Chrome** reward under these new rules and the first to an autonomous security company. Before the fixes were deployed, these vulnerabilities potentially exposed an estimated 1 billion **Chrome** users on **Windows**. **XBOW** founder Oege de Moor emphasized the implications of this speed: "It only took an estimated $40,000 of compute and six days for a single researcher to produce a chain that previously would have taken months." Dolan-Gavitt issued a clear warning for defenders: "Six days and $40k is not a lot of time or money when the payoff is a Chrome chain!" He concluded, "The bar, he wrote, is now much lower. Defend accordingly."