CVE-2022-40956: Mozilla Firefox

Medium severity, CVSS 6.1. EPSS: 0.9% chance of exploitation in the next 30 days.

When injecting an HTML base element, some requests would ignore the CSP's base-uri settings and accept the injected element's base instead. This vulnerability affects Firefox ESR < 102.3, Thunderbird < 102.3, and Firefox < 105.

Affected products

• Mozilla Firefox: before 105.0 (fixed in 105.0)
• Mozilla Firefox ESR: before 102.3 (fixed in 102.3)
• Mozilla Thunderbird: before 102.3 (fixed in 102.3)

Published 2022-12-22. Last modified 2026-06-17.