thunderbird is vulnerable to denial of service. An attacker is able to prevent a user from sending encrypted email to a correspondent via a malicious OpenPGP key with a subkey that has an invalid self signature.
access.redhat.com/errata/RHSA-2021:1193
access.redhat.com/security/updates/classification/#moderate
bugzilla.mozilla.org/show_bug.cgi?id=1666360
bugzilla.redhat.com/show_bug.cgi?id=1948395
www.mozilla.org/en-US/security/advisories/mfsa2021-13/#CVE-2021-23993
www.mozilla.org/en-US/security/advisories/mfsa2021-13/#CVE-2021-23993
www.mozilla.org/security/advisories/mfsa2021-13/