CVE-2026-18453 Null dereference in Red Hat Directory Server 11.5 E4S for RHEL 8
An unauthenticated remote attacker can crash the LDAP server by sending crafted search requests with the USE_ONE_BACKEND control, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-18453?
CVE-2026-18453 is a high-severity vulnerability in Red Hat Directory Server 11.5 E4S for RHEL 8, published on 7 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in 389 Directory Server. A missing NULL pointer check in the paged results handling of op_shared_search allows an unauthenticated remote attacker to crash the LDAP server by sending a crafted sequence of search requests using the USE_ONE_BACKEND control, resulting in denial of service.
Weakness: CWE-476
Which versions are affected by CVE-2026-18453?
How do I fix CVE-2026-18453?
Apply the vendor's patch.
Is CVE-2026-18453 being exploited?
There is no known exploitation of CVE-2026-18453 in the wild and no public exploit code.
Sources
Also known as AZL-99974, DEBIAN-CVE-2026-18453, GHSA-42wr-8m7m-5j62, UBUNTU-CVE-2026-18453.