The rwm overlay in OpenLDAP 2.4.23, 2.4.36, and earlier does not properly count references, which allows remote attackers to cause a denial of service (slapd crash) by unbinding immediately after a search request, which triggers rwm_conn_destroy to free the session context while it is being used by rwm_op_search.
https://support.apple.com/kb/HT210788
https://seclists.org/bugtraq/2019/Dec/23
https://bugzilla.redhat.com/show_bug.cgi?id=1019490
http://www.securitytracker.com/id/1029711
http://www.securityfocus.com/bid/63190
http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
http://www.openwall.com/lists/oss-security/2013/10/19/3
http://www.openldap.org/its/index.cgi/Incoming?id=7723
http://www.mandriva.com/security/advisories?name=MDVSA-2014:026
http://www.debian.org/security/2015/dsa-3209
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2013-4449
http://seclists.org/fulldisclosure/2019/Dec/26
http://rhn.redhat.com/errata/RHSA-2014-0206.html
http://rhn.redhat.com/errata/RHSA-2014-0126.html
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10735
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705