What’s Vulnerable › Vulnerabilities

CVE-2021-23992

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-24 · updated 2026-06-17
• Weakness: CWE-347

Description

Thunderbird did not check if the user ID associated with an OpenPGP key has a valid self signature. An attacker may create a crafted version of an OpenPGP key, by either replacing the original user ID, or by adding another user ID. If Thunderbird imports and accepts the crafted key, the Thunderbird user may falsely conclude that the false user ID belongs to the correspondent. This vulnerability affects Thunderbird < 78.9.1.

Affected products

• Mozilla Thunderbird: before 78.9.1 — fixed in 78.9.1

How to fix

Upgrade to a fixed version: Mozilla Thunderbird 78.9.1. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1666236
• https://www.mozilla.org/security/advisories/mfsa2021-13/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1666236
• https://www.mozilla.org/security/advisories/mfsa2021-13/

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