slapd/back-bdb/modrdn.c in the BDB backend for slapd in OpenLDAP 2.3.39 allows remote authenticated users to cause a denial of service (daemon crash) via a modrdn operation with a NOOP (LDAP_X_NO_OPERATION) control, a related issue to CVE-2007-6698.
The BDB backend for slapd in OpenLDAP before 2.3.36 allows remote authenticated users to cause a denial of service (crash) via a potentially-successful modify operation with the NOOP control set to critical, possibly due to a double free vulnerability.
servers/slapd/back-mdb/search.c in OpenLDAP through 2.4.44 is prone to a double free vulnerability. A user with access to search the directory can crash slapd by issuing a search including the Paged Results control with a page size of 0.