CVE-2025-4091
Memory safety bugs fixed in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10
CVSS Score
8.1
EPSS Score
0.0%
EPSS Percentile
0th
Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. 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 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbird 128.10.
| Vendor | mozilla |
| Product | firefox |
| Ecosystems | |
| Industries | Technology |
| Published | Apr 29, 2025 |
| Last Updated | Apr 13, 2026 |
Stay Ahead of the Next One
Get instant alerts for mozilla firefox
Be the first to know when new high vulnerabilities affecting mozilla firefox are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
Affected Versions
Mozilla / Firefox
All versions affected Mozilla / Thunderbird
All versions affected References
bugzilla.mozilla.org: https://bugzilla.mozilla.org/buglist.cgi?bug_id=1951161%2C1952105 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-28/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-29/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-31/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2025-32/ lists.debian.org: https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html
Credits
Maurice Dauer and the Mozilla Fuzzing Team