Description
When receiving an OpenPGP/MIME signed email message that contains an additional outer MIME message layer, for example a message footer added by a mailing list gateway, Thunderbird only considered the inner signed message for the signature validity. This gave the false impression that the additional contents were also covered by the digital signature. Starting with Thunderbird version 91.4.1, only the signature that belongs to the top level MIME part will be considered for the displayed status. This vulnerability affects Thunderbird < 91.4.1.
References (2)
Core 2
Core References
Issue Tracking, Permissions Required, Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1732310
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-55/
Scores
CVSS v3
6.5
EPSS
0.0034
EPSS Percentile
56.6%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
Status
published
Products (1)
mozilla/thunderbird
< 91.4.1
Published
Dec 22, 2022
Tracked Since
Feb 18, 2026