CVE-2026-100813: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.2% chance of exploitation in the next 30 days.

Invalid pointer in the JavaScript Engine: JIT component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.

Affected products

• Mozilla Firefox: before 157.0.0 (fixed in 157.0.0)
• Mozilla Thunderbird: before 157.0 (fixed in 157.0)

Published 2026-09-29. Last modified 2026-10-05.