Security researchers have detailed a critical exploit chain that achieves full system compromise, escalating from a Chrome renderer code execution vulnerability to kernel privileges using a technique involving MSG_OOB. This demonstrates a dangerous pathway for attackers to bypass browser sandboxing and gain deep control over affected systems, highlighting the complex nature of modern exploit development.

The exploit chain begins with an initial compromise of the Chrome renderer process, which is typically sandboxed to limit its impact on the host system. However, by chaining this with a subsequent kernel vulnerability, the attacker is able to break out of the sandbox and elevate their privileges to the highest level, effectively controlling the entire operating system.

Achieving Renderer Code Execution in Chrome

The first stage of the attack involves exploiting a vulnerability within the Chrome renderer. This vulnerability allows an attacker to execute arbitrary code within the sandboxed browser process. While significant, renderer code execution alone is usually contained, preventing broader system compromise due to Chrome’s security architecture. This initial breach serves as the launchpad for further escalation.

Kernel Privilege Escalation via MSG_OOB

The crucial second stage of the exploit utilizes a kernel vulnerability related to MSG_OOB (Message Out-of-Band) functionality. This specific flaw enables the attacker, already with code execution in the renderer, to manipulate kernel-level operations. By carefully crafting messages and exploiting the MSG_OOB mechanism, the attacker bypasses kernel security protections and achieves arbitrary code execution within the kernel context. This grants them full control over the operating system, allowing for complete system compromise and potential installation of persistent malware.

Source: https://googleprojectzero.blogspot.com/2025/08/from-chrome-renderer-code-exec-to-kernel.html