CVE-2026-12318: Mozilla Firefox

High severity, CVSS 7.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Incorrect boundary conditions in the Libraries component in NSS. 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.