An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (schema_init.c serialNumberAndIssuerCheck).
https://www.debian.org/security/2021/dsa-4845
https://support.apple.com/kb/HT212531
https://support.apple.com/kb/HT212530
https://support.apple.com/kb/HT212529
https://security.netapp.com/advisory/ntap-20210226-0002/
https://lists.debian.org/debian-lts-announce/2021/02/msg00005.html
https://git.openldap.org/openldap/openldap/-/tags/OPENLDAP_REL_ENG_2_4_57
https://git.openldap.org/openldap/openldap/-/commit/58c1748e81c843c5b6e61648d2a4d1d82b47e842
https://git.openldap.org/openldap/openldap/-/commit/38ac838e4150c626bbfa0082b7e2cf3a2bb4df31
https://bugs.openldap.org/show_bug.cgi?id=9424
https://bugs.openldap.org/show_bug.cgi?id=9404
http://seclists.org/fulldisclosure/2021/May/70