Description
Memory safety bug present in Firefox 143 and Thunderbird 143. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 144 and Thunderbird 144.
Affected products
mozilla: firefox; mozilla: thunderbird
References3
- www.mozilla.org/security/advisories/mfsa2025-81/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-84/ Vendor Advisory
- bugzilla.mozilla.org/show_bug.cgi?id=1986816 Issue TrackingPermissions Required
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 31 · as of 9 November 2026
- CWE
- CWE-119
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