A flaw was found in OpenLDAP in versions before 2.4.56. This flaw allows an attacker who sends a malicious packet processed by OpenLDAP to force a failed assertion in csnNormalize23(). The highest threat from this vulnerability is to system availability.
https://bugzilla.redhat.com/show_bug.cgi?id=1899678
https://lists.debian.org/debian-lts-announce/2020/12/msg00008.html