CVE-2026-2803: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Information disclosure, mitigation bypass in the Settings UI component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Affected products

• Mozilla Firefox: before 148.0 (fixed in 148.0)
• Mozilla Thunderbird: before 148.0 (fixed in 148.0)

Published 2026-02-24. Last modified 2026-06-17.