CVE-2026-74990

Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. 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 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

• CWE-119

• https://bugzilla.mozilla.org/buglist.cgi?bug_id=2045762%2C2052401%2C2058208Broken Link
• https://bugzilla.mozilla.org/buglist.cgi?bug_id=2045774%2C2048490%2C2050864%2C2053159%2C2053260%2C2053261%2C2053582%2C2053599%2C2053607%2C2053608%2C2053853%2C2054626%2C2054627%2C2054635%2C2054677%2C2054740%2C2054832%2C2056792%2C2057098%2C2057100%2C2057101%2C2057103%2C2057117%2C2057118%2C2058048%2C2058049%2C2058622%2C2058623%2C2058665%2C2058666%2C2059121%2C2059164%2C2059188Broken Link
• https://www.mozilla.org/security/advisories/mfsa2026-74/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2026-75/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2026-76/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2026-77/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2026-78/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2026-79/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2026-80/Vendor Advisory

Published

Aug 18, 2026

Last Modified

Aug 19, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
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