CVE-2026-86344: Denial-of-Service Vulnerability in Red Hat Directory Server

• •CVE-2026-86344 affects Red Hat Directory Server's 389-ds-base.
• •Unauthenticated attackers can exploit the flaw to cause denial-of-service.
• •No active exploitation has been confirmed; however, systems should be monitored.

A flaw in 389-ds-base allows unauthenticated remote attackers to exhaust the worker-thread pool, denying service to all clients. The vulnerability can be exploited by sending a complete LDAP operation followed by incomplete LDAPMessage bytes on the same connection. This results in blocking the connection mutex and preventing the delivery of completed operations. The attack can be sustained as long as the attacker maintains a small number of connections. Systems that are internet-accessible are at the highest risk, particularly those serving identity functions. The flaw does not affect data confidentiality or integrity, and normal service resumes quickly after the attack ends. As of now, no active exploitation has been confirmed, and the likelihood of exploitation remains uncertain. Administrators are advised to apply vendor patches promptly and limit concurrent LDAP connections from a single source IP.