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CVE-2026-84639

Uninitialized memory in MIME parsing

cve-program · severity unknownCVSS unknownCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-84639

Published

Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

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Affected versions, risk and source history

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CVE-2026-84639 · CVE overview and exploitation status

cve-program · CVE-2026-84639

https://bugzilla.mozilla.org/show_bug.cgi?id=2061087
https://www.mozilla.org/security/advisories/mfsa2026-86/
https://www.mozilla.org/security/advisories/mfsa2026-87/
https://www.mozilla.org/security/advisories/mfsa2026-88/

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