Multiple memory leaks in Red Hat Directory Server 7.1 before SP7, Red Hat Directory Server 8, and Fedora Directory Server 1.1.1 and earlier allow remote attackers to cause a denial of service (memory consumption) via vectors involving (1) the authentication / bind phase and (2) anonymous LDAP search requests.

It was discovered that Red Hat Directory Server and Fedora Directory Server is prone to a temporary denial of service attack (high CPU usage) via crafted LDAP search patterns. LDAP search patterns are internally translated to regular expressions. If the regular expression is matched against specially crafted record already stored in the LDAP, it may cause regular expression NFA to iterate over large amount of states, causing one slapd thread to occupy CPU for excessive amount of time.

Additionally, due to a current design of the regular expression handling code, only one slapd thread can execute regular expression NFA code at the time. Because of that, during the processing of such CPU intensive search request, all other search requests using patterns are blocked.

Affected version: Red Hat Directory Server 7.1 and 8 Fedora Directory Server 1.1.1