In Dovecot before 2.3.11.3, sending a specially formatted RPA request will crash the auth service because a length of zero is mishandled.
lists.opensuse.org/opensuse-security-announce/2020-08/msg00048.html
lists.opensuse.org/opensuse-security-announce/2020-08/msg00059.html
dovecot.org/security
lists.debian.org/debian-lts-announce/2020/08/msg00024.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4AAX2MJEULPVSRZOBX3PNPFSYP4FM4TT/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EYZU6CHA3VMYYAUCMHSCCQKJEVEIKPQ2/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XKKAL3OMG76ZZ7CIEMQP2K6KCTD2RAKE/
security.gentoo.org/glsa/202009-02
usn.ubuntu.com/4456-1/
usn.ubuntu.com/4456-2/
www.debian.org/security/2020/dsa-4745
www.openwall.com/lists/oss-security/2020/08/12/3