A NULL pointer dereference flaw exists in the 389-ds-base directory server. The issue is triggered when a ModifyDN (rename) operation supplies an attribute’s schema alias name (e.g., "commonName") instead of its canonical name (e.g., "cn") as the new relative distinguished name. An authenticated attacker who has ModifyDN permission on an entry can exploit this flaw to crash the directory server, resulting in a denial of service of the directory service and potentially any applications dependent on it.

The vulnerability affects Red Hat Directory Server versions 11, 12 and 13, as well as Red Hat Enterprise Linux releases 6 through 10 that include the 389-ds-base package. Deployments that have not added custom Access Control Instructions (ACIs) are not exposed, but any configuration that grants ModifyDN rights to non‑administrative users carries the risk.

The CVSS score of 6.5 indicates moderate severity. The EPSS score is not available, and the flaw is not listed in the CISA KEV catalog. Exploitation requires an authenticated attacker with ModifyDN permission on the target entry, as described in the vulnerability. The input does not specify a particular network access prerequisite or attack vector, so those details are unknown. The impact is limited to a crash that causes denial of service of the directory server and possibly dependent applications.