Fetchmail before 6.4.22 fails to enforce STARTTLS session encryption in some circumstances, such as a certain situation with IMAP and PREAUTH.
www.openwall.com/lists/oss-security/2021/08/27/3
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3XJ6XLEJCEZCAM5LGGD6XBCC522QLG4/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VXMKSEHAQSEDCWZMAOJEGX3P3JW6QY6H/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZYCYLL73NP7ALJWSDICIVSA47ZIXWSSA/
nostarttls.secvuln.info/
security.gentoo.org/glsa/202209-14
www.fetchmail.info/security.html