CVE-2022-1834

When displaying the sender of an email, and the sender name contained the
Braille Pattern Blank space character multiple times, Thunderbird would
have displayed all the spaces. This could have been used by an attacker to
send an email message with the attacker’s digital signature, that was shown
with an arbitrary sender email address chosen by the attacker. If the
sender name started with a false email address, followed by many Braille
space characters, the attacker’s email address was not visible. Because
Thunderbird compared the invisible sender address with the signature’s
email address, if the signing key or certificate was accepted by
Thunderbird, the email was shown as having a valid digital signature. This
vulnerability affects Thunderbird < 91.10.