389 Directory Server NULL Pointer Crash via USE_ONE_BACKEND Control
CVE-2026-18453 Published on September 7, 2026

389-ds-base: 389-ds-base: pre-authentication null pointer dereference via paged results and use_one_backend control in op_shared_search
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.

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Vulnerability Analysis

CVE-2026-18453 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 61 days later.

Weakness Type

NULL Pointer Dereference

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.


Products Associated with CVE-2026-18453

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Red Hat Directory Server
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Rhel Els
 
Red Hat Directory Server E4s
 
Red Hat Rhel Aus
 
Red Hat Rhel Eus Long Life
 
Red Hat Rhel E4s
 
Red Hat Rhel Tus
 
Red Hat Enterprise Linux Eus
 
Red Hat Rhel Eus
 

Affected Versions

Red Hat Directory Server 11.7 E4S for RHEL 8: Red Hat Directory Server 11.9 for RHEL 8: Red Hat Directory Server 12.2 E4S for RHEL 9: Red Hat Directory Server 12.4 E4S for RHEL 9: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10.0 Extended Update Support: Red Hat Enterprise Linux 7 Extended Lifecycle Support: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.8 Telecommunications Update Service: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Directory Server 13.2: Red Hat Directory Server 12: Red Hat Directory Server 13: Red Hat Enterprise Linux 6:

Exploit Probability

EPSS
0.85%
Percentile
56.37%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.