CVE-2026-22400: Holmes Theme Authorization Bypass Flaw

CVE-2026-22400 Overview

CVE-2026-22400 is an Authorization Bypass Through User-Controlled Key vulnerability affecting the Holmes WordPress theme developed by Mikado-Themes. This vulnerability, also known as Insecure Direct Object Reference (IDOR), allows attackers to exploit incorrectly configured access control security levels by manipulating user-controlled parameters to access or modify resources belonging to other users.

Critical Impact

Attackers can bypass authorization controls by manipulating object references, potentially gaining unauthorized access to sensitive data or functionality belonging to other users on affected WordPress sites.

Affected Products

• Holmes WordPress Theme version 1.7 and earlier
• All prior versions of Holmes theme (from n/a through 1.7)
• WordPress installations running vulnerable Holmes theme versions

Discovery Timeline

• 2026-01-22 - CVE-2026-22400 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2026-22400

Vulnerability Analysis

This vulnerability is classified as CWE-639: Authorization Bypass Through User-Controlled Key. The Holmes WordPress theme fails to properly validate that users are authorized to access specific resources before serving them. Instead of verifying ownership or permissions server-side, the theme relies on user-supplied identifiers to determine which resources to access or modify.

When an application uses user-controllable keys (such as IDs, filenames, or other identifiers) to directly reference internal objects without proper authorization checks, attackers can modify these references to access resources belonging to other users. This represents a fundamental flaw in the access control implementation of the affected theme.

Root Cause

The root cause of this vulnerability lies in the Holmes theme's failure to implement proper authorization validation when handling object references. The theme accepts user-controlled identifiers and uses them to retrieve or manipulate data without verifying that the requesting user has legitimate permission to access the referenced objects. This design flaw allows attackers to enumerate and access resources by simply modifying the object reference parameters in requests.

Attack Vector

The attack vector involves manipulating user-controlled parameters in HTTP requests to the WordPress site running the vulnerable Holmes theme. An attacker would typically:

1. Identify endpoints that accept object identifiers (such as post IDs, user IDs, or other numeric/string references)
2. Observe legitimate requests to understand the parameter structure
3. Modify the object reference value to point to resources belonging to other users
4. Access unauthorized data or perform unauthorized actions on those resources

Since no verified code examples are available for this vulnerability, the specific exploitation mechanism involves manipulating HTTP request parameters that reference internal WordPress or theme objects. For detailed technical information, refer to the Patchstack WordPress Vulnerability Report.

Detection Methods for CVE-2026-22400

Indicators of Compromise

• Unusual access patterns to WordPress resources from single IP addresses with sequential or enumerated object IDs
• Web server logs showing repeated requests with incrementing or modified identifier parameters
• Evidence of unauthorized data access or modification in WordPress audit logs
• Multiple failed authorization attempts followed by successful access to different user resources

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block sequential ID enumeration attempts
• Monitor WordPress access logs for patterns of parameter manipulation targeting object references
• Deploy file integrity monitoring on WordPress installations to detect unauthorized modifications
• Review audit logs for cross-user data access anomalies

Monitoring Recommendations

• Enable comprehensive logging for all WordPress theme-related requests
• Set up alerts for unusual access patterns to user-specific resources
• Monitor for brute-force attempts against object reference parameters
• Implement rate limiting on endpoints that handle object references

How to Mitigate CVE-2026-22400

Immediate Actions Required

• Update the Holmes WordPress theme to the latest patched version when available from Mikado-Themes
• Consider temporarily disabling the Holmes theme and switching to a secure alternative until a patch is released
• Implement additional authorization checks at the WordPress or web server level
• Review access logs for signs of exploitation attempts

Patch Information

Organizations should monitor the Patchstack WordPress Vulnerability Report for official patch announcements from Mikado-Themes. Update to a version higher than 1.7 once a security fix is released.

Workarounds

• Deploy a Web Application Firewall (WAF) with rules to detect and block IDOR attack patterns
• Implement server-side access controls independent of the theme's built-in authorization
• Restrict access to sensitive functionality through WordPress user role management
• Consider using security plugins that provide additional access control layers for WordPress themes

# WordPress security hardening example - restrict direct theme access
# Add to .htaccess in WordPress root directory
<IfModule mod_rewrite.c>
RewriteEngine On
# Block direct access to theme PHP files
RewriteRule ^wp-content/themes/holmes/.*\.php$ - [F,L]
</IfModule>