Denial of Service Vulnerability in 389 Directory Server by Red Hat
CVE-2026-18453

7.5HIGH

Key Information:

Vendor

Red Hat
Status
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
Vendor
CVE Published:
7 September 2026

What is CVE-2026-18453?

A vulnerability has been identified in 389 Directory Server, where a missing NULL pointer check in the paged results handling of op_shared_search can be exploited by an unauthenticated remote attacker. By sending a carefully crafted series of search requests using the USE_ONE_BACKEND control, an attacker can crash the LDAP server, leading to a denial of service. This issue underscores the importance of implementing robust input validation to mitigate such risks.

Affected Version(s)

Red Hat Directory Server 11.7 E4S for RHEL 8 8080020260903102346.f969626e

Red Hat Directory Server 11.9 for RHEL 8 8100020260904171440.37ed7c03

Red Hat Directory Server 12.2 E4S for RHEL 9 9020020260903155914.1674d574

References

https://access.redhat.com/errata/RHSA-2026:64771
vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:64776
vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:64778
vendor-advisoryx_refsource_REDHAT

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Arthur Chan (Ada Logics) and Team (Anthropic) for reporting this issue.
.