Unrated severityNVD Advisory· Published Sep 1, 2026

CVE-2026-84641

Description

A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Affected products

Mozilla Corporation/Thunderbirdllm-fuzzy
Range: before 155, before 140.15, before 153.2

Patches

Vulnerability mechanics

References

bugzilla.mozilla.org/show_bug.cginvd
www.mozilla.org/security/advisories/mfsa2026-86/nvd
www.mozilla.org/security/advisories/mfsa2026-87/nvd
www.mozilla.org/security/advisories/mfsa2026-88/nvd

News mentions

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