CVE-2026-87499 is an authorization bypass vulnerability in the Network component of Google Chrome before version 153.0.8010.36. It allows a remote attacker who has compromised the renderer process to bypass site isolation protections by leveraging a crafted HTML page. This flaw is categorized under CWE-863 (Incorrect Authorization). The vulnerability was assigned a high severity by Chromium security but lacks a CVSS score and known active exploitation. No explicit vendor advisory or patch link is provided in the data, but the fixed version is indicated as 153.0.8010.36.

Successful exploitation enables an attacker with control over the renderer process to bypass site isolation, potentially allowing access to data or processes that should be isolated between sites. This could lead to increased risk of data leakage or unauthorized access within the browser context. However, exploitation requires prior compromise of the renderer process.

A fix is available in Google Chrome version 153.0.8010.36. Users and administrators should update to this version or later to remediate the vulnerability. Since this is a client software vulnerability, updating the browser is the primary mitigation step. No additional vendor advisory content is provided to indicate other mitigations or if no action is required.