CVE-2026-76033 is a vulnerability in Google Chrome's implementation of Cross-Origin Resource Sharing (CORS) prior to version 151.0.7922.169. The flaw allows a remote attacker, who has already compromised the renderer process, to bypass site isolation protections by using a specially crafted HTML page. Site isolation is a critical security feature designed to separate different websites into different processes to prevent data leakage and cross-site attacks. This vulnerability undermines that protection, potentially exposing sensitive data across site boundaries.

The vulnerability enables an attacker with control over the renderer process to bypass Chrome's site isolation feature, which could lead to unauthorized access to data from other sites within the browser. This compromises the browser's security model and can facilitate further exploitation or data theft within the affected browser instance.

Google has released Chrome version 151.0.7922.169 to address this vulnerability. Users and administrators should update to this version or later to mitigate the risk. Since this is a client-side browser vulnerability, applying the official update is the primary remediation step.