Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Thunderbird | < 91.4.1 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1732310Issue TrackingPermissions RequiredVendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-55/Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1732310Issue TrackingPermissions RequiredVendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-55/Vendor Advisory
FAQ
What is CVE-2021-4126?
CVE-2021-4126 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 ...
How severe is CVE-2021-4126?
CVE-2021-4126 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-4126?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Thunderbird.