CVE-2026-24072: Apache HTTP Server Privilege Escalation

CVE-2026-24072 Overview

CVE-2026-24072 is a privilege escalation vulnerability affecting multiple modules in Apache HTTP Server version 2.4.66 and earlier. The flaw allows local authors of .htaccess files to read files with the privileges of the httpd user. This expands the effective access of an .htaccess author beyond their own permissions, exposing files that should remain restricted to the web server process. The Apache HTTP Server project has released version 2.4.67 to address this issue. The weakness is classified under CWE-269: Improper Privilege Management.

Critical Impact

A local user with .htaccess authoring rights can read any file readable by the Apache httpd process, including configuration files and credentials accessible to the web server account.

Affected Products

• Apache HTTP Server 2.4.66 and earlier 2.4.x releases
• Deployments using .htaccess overrides across various Apache modules
• Multi-tenant hosting environments where untrusted users author .htaccess files

Discovery Timeline

• 2026-05-04 - CVE-2026-24072 published to NVD
• 2026-05-04 - Last updated in NVD database

Technical Details for CVE-2026-24072

Vulnerability Analysis

The vulnerability resides in how various Apache HTTP Server modules process directives placed inside .htaccess files. Apache permits per-directory configuration through these files when AllowOverride is enabled. A local user able to author an .htaccess file can craft directives that cause the server to read files using the privileges of the httpd user. The author then receives the contents through normal HTTP responses or module side effects. The Apache advisory tracks this as a privilege management defect across multiple modules rather than a single component flaw.

Root Cause

The root cause is improper privilege management [CWE-269] within affected modules that act on .htaccess-supplied paths or references. The modules execute file access operations under the httpd process identity without restricting those operations to files the originating local user is authorized to read. This breaks the expected boundary between .htaccess authoring rights and the broader file system access available to the web server account.

Attack Vector

Exploitation requires a local user who can write .htaccess files served by the vulnerable Apache instance. This is common in shared hosting, lab, and development environments. The attacker places directives in an .htaccess file inside a directory served by Apache. When the server processes a request that triggers the affected module, it reads the targeted file with httpd privileges and exposes the contents to the attacker. No memory corruption or external network foothold is required beyond the ability to issue HTTP requests against the server. Refer to the Apache HTTP Server Vulnerabilities advisory and the Openwall OSS-Security post for module-level technical detail.

Detection Methods for CVE-2026-24072

Indicators of Compromise

• Unexpected .htaccess files referencing absolute paths outside the user's own directory tree.
• HTTP responses or error log entries showing access to files outside published document roots.
• Apache httpd process reading sensitive files such as /etc/, application secrets, or other tenants' content.

Detection Strategies

• Audit all .htaccess files on multi-tenant servers for directives that reference paths outside the owning user's home directory.
• Compare the running Apache version against 2.4.67 using httpd -v and flag any host at or below 2.4.66.
• Review Apache access_log and error_log for requests that correlate with file reads at unusual paths.

Monitoring Recommendations

• Enable file integrity monitoring on .htaccess files in user-writable directories and alert on creation or modification.
• Monitor httpd process file access using auditd rules targeting reads of sensitive paths by the web server UID.
• Forward Apache logs to a centralized analytics platform and alert on response patterns that indicate cross-tenant file reads.

How to Mitigate CVE-2026-24072

Immediate Actions Required

• Upgrade Apache HTTP Server to version 2.4.67 or later on all affected hosts.
• Inventory shared hosting and development servers where untrusted users can author .htaccess files and prioritize those for patching.
• Review and tighten AllowOverride directives so only required override classes are permitted in user directories.

Patch Information

Apache HTTP Server 2.4.67 fixes the privilege escalation across the affected modules. Consult the Apache HTTP Server 2.4 Vulnerabilities page for the authoritative patch entry and module-level notes. Distribution maintainers typically backport the fix to packaged 2.4.x builds; verify your vendor's package version contains the patch before relying on the package number alone.

Workarounds

• Set AllowOverride None in httpd.conf for directories where .htaccess authoring is not strictly required, eliminating the attack surface.
• Restrict the AllowOverrideList to a minimal set of directives that does not include those exposed by the vulnerable modules until patches are deployed.
• Run untrusted virtual hosts under separate user identities using mechanisms such as mod_ruid2 or per-user PHP-FPM pools to reduce the value of the httpd privilege.

# Configuration example: disable .htaccess overrides where possible
<Directory "/var/www">
    AllowOverride None
    Require all granted
</Directory>

# Verify installed Apache version after upgrade
httpd -v
# Expected: Server version: Apache/2.4.67 or later