CVE-2026-74957 is a security vulnerability involving a mitigation bypass in the Safe Browsing component of Mozilla Firefox. This flaw could potentially allow attackers to circumvent security protections implemented by the Safe Browsing feature. Mozilla fixed this vulnerability in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The advisory categorizes the impact as moderate and no active exploitation in the wild has been reported. The fix is part of a broader security update addressing multiple vulnerabilities.

The vulnerability allows bypassing mitigation controls in the Safe Browsing component, which could reduce the effectiveness of security protections against malicious sites or content. The impact is assessed as moderate by the vendor, indicating a meaningful but not critical risk to users if exploited.

Users and administrators should update Mozilla Firefox to version 154 or later, or Firefox ESR to version 140.14 or later (including ESR 153.1), where this vulnerability has been fixed. Applying these official updates fully mitigates the issue. No additional mitigation actions are required beyond applying the vendor-provided patches.