CVE-2026-76560

A flaw was found in 389 Directory Server. The SELFDN ACI bind-rule evaluator incorrectly matches an anonymous LDAP client's empty bind DN against an empty stored attribute value, allowing an unauthenticated client to satisfy access control checks intended to require a matching authenticated identity. This can allow an anonymous LDAP client to perform an operation, such as adding or modifying a directory entry, that a SELFDN-based ACI intended to restrict to a specific authenticated user.

This flaw affects any 389 Directory Server (or Red Hat Directory Server) deployment that defines an ACI using a userattr="attribute#SELFDN" or userattr="attribute#USERDN" bind rule on an attribute that is permitted to hold an explicit empty value. Red Hat Directory Server does not ship such an ACI by default; real-world impact depends on whether a specific deployment or consuming application defines an ACI of this shape.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Until a fix is available, review all ACIs using userattr="...#SELFDN" bind rules and confirm the target attribute cannot be set to an empty value, or add an explicit authmethod restriction to the ACI to prevent anonymous binds from satisfying the check. Where anonymous binds are not required, disabling anonymous access to the directory removes the attack surface entirely.