Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://www.mozilla.org/security/advisories/mfsa2026-25/ Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 9.8 · mozillaNVD modified 2026-10-23 23:10
Affected (CPE criteria) 2
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
References 6
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2025475%2C2025477 Broken Link, Issue Tracking
- https://www.mozilla.org/security/advisories/mfsa2026-25/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-28/
- https://access.redhat.com/security/cve/CVE-2026-5735
- https://bugzilla.redhat.com/show_bug.cgi?id=2455904
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5735.json