LibEtPan through 1.9.4, as used in MailCore 2 through 0.6.3 and other products, has a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a “begin TLS” response, the client reads additional data (e.g., from a meddler-in-the-middle attacker) and evaluates it in a TLS context, aka “response injection.”
lists.opensuse.org/opensuse-security-announce/2020-09/msg00060.html
lists.opensuse.org/opensuse-security-announce/2020-09/msg00075.html
github.com/dinhvh/libetpan/issues/386
lists.debian.org/debian-lts-announce/2020/08/msg00026.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M65FVH5XPS23NLHFN3ABEGBSCHZAISXN/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QFBWNA5REI5ZGW2DAOEAVHM23MOU6O5J/
security.gentoo.org/glsa/202007-55