Is CVE-2026-18453 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-18453 being exploited in the wild.

How severe is CVE-2026-18453?

High severity, with a CVSS score of 7.5, published 7 September 2026.

Which products and versions are affected?

389 Project 389 Directory Server.

Is there a fix for CVE-2026-18453?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-18453 attacked?

It is attacked over the network.

Am I affected by CVE-2026-18453?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-18453: 389 Directory Server NULL pointer dereference in paged results

CVE-2026-18453 · Severity: high · CVSS 7.5 · Published 2026-09-07

A flaw in 389 Directory Server, a widely-used LDAP directory service, allows an unauthenticated attacker to crash the server by sending specially crafted search requests. An exploitable crash results in denial of service, making the directory service unavailable to legitimate users and potentially disrupting authentication and organizational operations that depend on it.

Quick answers

Is CVE-2026-18453 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-18453 being exploited in the wild.
How severe is CVE-2026-18453?: High severity, with a CVSS score of 7.5, published 7 September 2026.
Which products and versions are affected?: 389 Project 389 Directory Server.
Is there a fix for CVE-2026-18453?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-18453 attacked?: It is attacked over the network.
Am I affected by CVE-2026-18453?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A missing NULL pointer check in the paged results handling of the op_shared_search function allows a NULL pointer dereference. An unauthenticated remote attacker can exploit this by sending a crafted sequence of LDAP search requests that use the USE_ONE_BACKEND control, triggering a crash of the LDAP server process. The vulnerability requires no authentication or user interaction and is reachable over the network. An attacker can achieve denial of service by repeatedly crashing the service. Patches are expected from Red Hat and upstream 389 Project.

Affected products

389 Project 389 Directory Server

Timeline

2026-09-07: disclosed

References

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