CVE-2026-84641

Summary

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 Software

VendorProductVersion RangeStatus
MozillaThunderbird140.15 <= 140.*unaffected
MozillaThunderbird153.2 <= 153.*unaffected
MozillaThunderbird155 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References