CVE-2025-4091

Description

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.

PUBLISHED Reserved 2025-04-29 | Published 2025-04-29 | Updated 2026-04-13 | Assigner mozilla

Product status

Credits

Maurice Dauer and the Mozilla Fuzzing Team

References

lists.debian.org/debian-lts-announce/2025/05/msg00024.html

bugzilla.mozilla.org/buglist.cgi?bug_id=1951161%2C1952105 (Memory safety bugs fixed in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10)

www.mozilla.org/security/advisories/mfsa2025-28/

www.mozilla.org/security/advisories/mfsa2025-29/

www.mozilla.org/security/advisories/mfsa2025-31/

www.mozilla.org/security/advisories/mfsa2025-32/

cve.org (CVE-2025-4091)

nvd.nist.gov (CVE-2025-4091)

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