Description
Memory safety bugs present in Firefox ESR 140.2, Thunderbird ESR 140.2, Firefox 142 and Thunderbird 142. 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 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird 140.3.
Affected products
mozilla: firefox; mozilla: thunderbird
References7
- www.mozilla.org/security/advisories/mfsa2025-73/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-75/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-77/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-78/ Vendor Advisory
- bugzilla.mozilla.org/buglist.cgi?bug_id=1938220%2C1980730%2C198… Issue Tracking
- lists.debian.org/debian-lts-announce/2025/09/msg00020.html
- lists.debian.org/debian-lts-announce/2025/09/msg00026.html
Metrics
- CVSS 3.1
-
8.8
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 28 · as of 8 November 2026
- CWE
- CWE-119
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