CVE-2026-8974
Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151
CVSS Score
8.8
EPSS Score
0.0%
EPSS Percentile
14th
Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
| Vendor | mozilla |
| Product | firefox |
| Ecosystems | |
| Industries | Technology |
| Published | May 19, 2026 |
| Last Updated | May 20, 2026 |
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Affected Versions
Mozilla / Firefox
All versions affected Mozilla / Thunderbird
All versions affected References
bugzilla.mozilla.org: https://bugzilla.mozilla.org/buglist.cgi?bug_id=1784128%2C1883230%2C1983677%2C2022390%2C2023116%2C2023657%2C2024255%2C2024418%2C2024441%2C2024447%2C2024966%2C2025412%2C2025467%2C2025940%2C2025950%2C2025956%2C2026284%2C2027247%2C2027255%2C2027288%2C2027306%2C2027322%2C2027332%2C2027333%2C2028266%2C2028292%2C2028319%2C2028526%2C2028870%2C2028876%2C2028882%2C2029062%2C2029309%2C2029414%2C2029422%2C2029428%2C2029447%2C2029732%2C2029785%2C2029793%2C2029813%2C2029899%2C2031028%2C2031457%2C2032039%2C2033610%2C2033854%2C2034498%2C2034628%2C2034978%2C2035966%2C2036668%2C2036905%2C2036930 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-46/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-48/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-50/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-51/
Credits
Nika Layzell, Randell Jesup, Timothy Nikkel, Tom Schuster and the Mozilla Fuzzing Team