CVE-2026-11063: Insufficient validation of untrusted input in WebNN in Google Chrome on Windows prior to 149

Synopsis

This is a sandbox escape vulnerability in Google Chrome's WebNN component on Windows, caused by insufficient validation of untrusted input. The flaw is reachable over the network and requires no authentication, but does require a victim to interact with a crafted HTML page; exploitation also requires that the attacker has already compromised the renderer process. Successful exploitation allows a remote attacker to break out of Chrome's sandbox, gaining capabilities beyond the browser process, including full confidentiality, integrity, and availability impact on the host. A patched-image rebuild at version 149.0.7827.53 is available on HarborGuard for environments running an affected version of Chrome.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker delivers the exploit over the network by directing a victim to a crafted HTML page, so the vulnerable Chrome instance must be reachable from an internet-facing or network-adjacent context.

• AuthenticationNot required

  No account or credential of any kind is needed; the attack can be launched by any unauthenticated remote party.

• Victim interactionRequired

  The victim must open or be redirected to a crafted HTML page, making social engineering or a malicious-link delivery mechanism a prerequisite.

• Attack complexityDetail

  Attack complexity is low, meaning the exploit is reliable and does not depend on race conditions or specific memory layout; however, the attacker must separately have compromised the renderer process before leveraging this sandbox escape.

Blast Radius

• Attacker escapes Chrome's sandbox and executes code at the privilege level of the browser process on the Windows host, bypassing the containment layer that normally limits renderer compromise.
• Full confidentiality impact: the escaped process reads files, credentials, and session data accessible to the Chrome user account on the host.
• Full integrity impact: the escaped process writes or modifies files, registry keys, and persisted data on the host.
• Full availability impact: the escaped process can terminate processes, corrupt data, or otherwise crash or destabilize the host environment.