Improper Verification of Cryptographic Signature
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.
CWE-347 - Improper Verification of Cryptographic Signature
A cryptographic protocol is meant to ensure that services are provided in a secure manner. An application with absent or improper verification of cryptographic signatures allows malicious users to feed false messages to valid users or to disclose sensitive data, subverting the goals of the protocol. This can lead to security failures such as false authentication, account hijacking, and privilege escalation.