🔐 CVE Alert

CVE-2026-84145

HIGH 7.5

Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15

CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th

Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Vendor mozilla
Product firefox
Ecosystems
Industries
Technology
Published Sep 1, 2026
Last Updated Sep 2, 2026
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Affected Versions

Mozilla / Firefox
All versions affected
Mozilla / Thunderbird
All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗
bugzilla.mozilla.org: https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054640%2C2054650%2C2054652%2C2055693%2C2055705%2C2058051%2C2058652%2C2058660%2C2059027%2C2061220%2C2061242%2C2061285%2C2061300%2C2061316%2C2061397 bugzilla.mozilla.org: https://bugzilla.mozilla.org/buglist.cgi?bug_id=2058001%2C2059139%2C2062400%2C2062419 bugzilla.mozilla.org: https://bugzilla.mozilla.org/show_bug.cgi?id=2055678 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-82/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-83/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-84/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-85/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-86/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-87/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-88/

Credits

Leo Tenenbaum, Tom Ritter and the Mozilla Fuzzing Team