CVE-2026-0881

Sandbox escape in the Messaging System component. This vulnerability affects Firefox < 147 and Thunderbird < 147.

• https://bugzilla.mozilla.org/show_bug.cgi?id=2005845
• https://www.mozilla.org/security/advisories/mfsa2026-01/
• https://www.mozilla.org/security/advisories/mfsa2026-04/