Description
Memory safety bugs present in Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, 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, Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
Affected products
mozilla: firefox; mozilla: thunderbird
References10
- www.mozilla.org/security/advisories/mfsa2026-25/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-26/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-27/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-28/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-29/ Vendor Advisory
- bugzilla.mozilla.org/buglist.cgi?bug_id=2021894%2C2022225%2C202… Broken Link
- access.redhat.com/errata/RHSA-2026:11805
- access.redhat.com/errata/RHSA-2026:11813
- access.redhat.com/errata/RHSA-2026:12264
- access.redhat.com/errata/RHSA-2026:13342
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 29 · as of 12 November 2026
- CWE
- CWE-119CWE-787
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