CVE-2026-87577 is an authorization bypass vulnerability in Google Chrome's Isolated feature affecting versions prior to 153.0.8010.36. The flaw allows a remote attacker to circumvent the web origin policy, which normally restricts web pages from accessing resources outside their origin, thereby gaining access to privileged pages through a specially crafted HTML page. The vulnerability is categorized under CWE-863 (Incorrect Authorization). There is no CVSS score or detailed vendor advisory provided, and no known exploits are reported in the wild.

Successful exploitation could allow a remote attacker to bypass web origin policy restrictions and access privileged pages within the browser context. This could lead to unauthorized access to sensitive browser features or data that should be isolated. The severity is considered medium by Chromium security standards.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should exercise caution when visiting untrusted websites and consider applying any available browser updates promptly once published.