CVE-2022-29909: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.9% chance of exploitation in the next 30 days.

Documents in deeply-nested cross-origin browsing contexts could have obtained permissions granted to the top-level origin, bypassing the existing prompt and wrongfully inheriting the top-level permissions. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.

Affected products

• Mozilla Firefox: before 100.0 (fixed in 100.0)
• Mozilla Firefox ESR: before 91.9 (fixed in 91.9)
• Mozilla Thunderbird: before 91.9 (fixed in 91.9)

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