CVE-2026-29167: Use After Free vulnerability in Apache HTTP Server with mod_ldap in per-directory configuration This issue affects Apache HTTP Server: from 2.4.0 through…

PriorityP259critical9.8CVSS 3.1

AVNACLPRNUINSUCHIHAH

EPSS

0.66%

47.0th percentile

Use After Free vulnerability in Apache HTTP Server with mod_ldap in per-directory configuration This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
apache	http_server	>= 2.4.0 < 2.4.68	2.4.68
apache	httpd	—	—
apache_software_foundation	apache_http_server	2.4.0 – 2.4.67	—

Detection & IOCsextracted from sources · hover to see the quote

→Vulnerability is only triggerable when mod_ldap is loaded AND configured in a per-directory context (<Directory>, <Location>, <Files>, or .htaccess). Server-wide LDAP configuration does not trigger the use-after-free. ↗
→The UAF occurs in the per-directory configuration merge path, not in the hot request-handling path. Detection focus should be on config-merge-time crashes (child process segfaults) in Apache prefork/worker/event MPMs when mod_ldap per-directory config is present. ↗
→Realistic exploitation outcome is a transient DoS via child process segfault (parent respawns workers). Monitor Apache error logs for repeated child process crashes (segfaults) when mod_ldap per-directory config is active. ↗
→Affected version range is Apache HTTP Server 2.4.0 through 2.4.67. Audit deployed httpd version strings to identify vulnerable instances. ↗

·mod_ldap is not loaded by default in Apache HTTP Server. The vulnerability only manifests when mod_ldap is explicitly loaded AND LDAP directives are placed in a per-directory context (<Directory>, <Location>, <Files>, or .htaccess). Server-wide LDAP configuration is NOT affected. ↗
·RCE reliability is substantially reduced by Apache's process model. In prefork MPM, a crash kills only one child process and the parent respawns it. In worker/event MPMs, per-process address space isolation further limits exploit reliability. Practical impact is most likely transient DoS, not code execution. ↗

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

vendor_redhat9.8CRITICAL

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