CVE-2026-12316: Mozilla Firefox

Critical severity, CVSS 9.1. EPSS: 0.2% chance of exploitation in the next 30 days.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.

Affected products

• Mozilla Firefox: before 152.0.0 (fixed in 152.0.0)
• Mozilla Thunderbird: before 152.0.0 (fixed in 152.0.0)

Published 2026-06-16. Last modified 2026-06-17.