Red Hat Directory Server/Enterprise Linux LDAP Connection resource consumption

Summaryinfo

A vulnerability was found in Red Hat Directory Server and Enterprise Linux. It has been declared as critical. Impacted is an unknown function of the component LDAP Connection Handler. The manipulation results in resource consumption. This vulnerability is cataloged as CVE-2026-86344. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as critical, was found in Red Hat Directory Server and Enterprise Linux (version now known). Affected is some unknown processing of the component LDAP Connection Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

A flaw was found in 389-ds-base. An unauthenticated remote attacker can send a complete LDAP operation followed by the first bytes of an incomplete LDAPMessage on the same connection, causing the server to hand that connection to a second worker thread before the first worker's result is flushed. The second worker blocks until nsslapd-ioblocktimeout while holding the connection mutex, preventing delivery of the completed operation's result. Repeating this across a small number of connections proportional to the configured worker-thread pool size exhausts the entire pool under default configuration, denying service to all clients (anonymous and authenticated, plaintext and TLS) for as long as the attacker maintains the connections.

The advisory is shared for download at access.redhat.com. This vulnerability is traded as CVE-2026-86344 since 09/07/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/01/2026). The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Directory Service Software

Vendor

• Red Hat

Name

• Directory Server
• Enterprise Linux

License

• open-source

Website

• Vendor: https://www.redhat.com/

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