CVE-2026-18453
Received Received - Intake

BaseFortify

Publication date: 2026-09-07

Last updated on: 2026-09-07

Assigner: redhat-SADP

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.

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Meta Information

Published
2026-09-07
Last Modified
2026-09-07
Generated
2026-09-07
AI Q&A
2026-09-07
EPSS Evaluated
N/A
NVD
CVE-2026-18453
EUVD
EUVD-2026-72456

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
redhat 389_directory_server *
redhat 389-ds-base *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.

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Executive Summary

This vulnerability is a NULL pointer dereference flaw in 389 Directory Server. It occurs in the paged results handling of the op_shared_search function. An unauthenticated remote attacker can exploit it by sending crafted search requests using the USE_ONE_BACKEND control, causing the LDAP server to crash and deny service.

Detection Guidance

Monitor for crashes of the ns-slapd process in 389 Directory Server logs. Check for repeated LDAP search requests using the USE_ONE_BACKEND control with paged results. Use network traffic analysis tools to detect crafted search sequences targeting the op_shared_search function.

Impact Analysis

This vulnerability allows an attacker to crash the LDAP server remotely without authentication, stopping directory lookups and authentication services. The server must be restarted to restore functionality. Confidentiality and integrity are not affected as the issue only causes a crash.

Compliance Impact

This vulnerability causes a denial of service by crashing the LDAP server, which could disrupt authentication and directory lookup services. For GDPR, this may impact availability of personal data processing systems. For HIPAA, it could disrupt access to protected health information systems. Both standards require availability of critical systems handling sensitive data.

Mitigation Strategies

Update the 389 Directory Server package to the latest patched version immediately. Disable anonymous LDAP access if not required. Restrict LDAP service access to trusted networks only. Monitor for crashes and restart the ns-slapd process if affected.

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