CVE-2026-100810: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 0.4% chance of exploitation in the next 30 days.

Other issue in the DevTools 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.