CVE Catalog

CVE-2026-86344

HighCVSS 7.5
Published: Translated: NVD NIST

Summary

A flaw was found in 389-ds-base where 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.

Risk Assessment

The attack can lead to complete denial of service, preventing all clients from using the LDAP server, potentially disrupting the entire infrastructure.

Recommendation

Upgrade 389-ds-base to the latest patched version or adjust configuration to mitigate risk, e.g., increasing the block timeout limit.

Other vulnerabilities in 389-ds-base

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS