CVE-2025-12158: WordPress Simple User Capabilities Plugin

CVE-2025-12158 Overview

The Simple User Capabilities plugin for WordPress contains a critical Privilege Escalation vulnerability due to a missing capability check on the suc_submit_capabilities() function. This flaw affects all versions up to and including 1.0, allowing unauthenticated attackers to elevate the role of any user account to administrator, effectively granting complete control over the affected WordPress installation.

Critical Impact

Unauthenticated attackers can escalate any user account to administrator privileges, enabling full site takeover without requiring any authentication.

Affected Products

• Simple User Capabilities plugin for WordPress versions up to and including 1.0

Discovery Timeline

• 2025-11-04 - CVE-2025-12158 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2025-12158

Vulnerability Analysis

This vulnerability is classified under CWE-862 (Missing Authorization), which occurs when a software system does not perform an authorization check when an actor attempts to access a resource or perform an action. The suc_submit_capabilities() function fails to verify that the requesting user has appropriate administrative privileges before processing capability modification requests.

The vulnerability allows attackers to manipulate user roles through the WordPress AJAX interface without any authentication requirements. Since the function processes role elevation requests without proper capability checks, malicious actors can target any existing user account and grant it administrator-level access. This represents a complete bypass of WordPress's built-in role-based access control system.

Root Cause

The root cause of this vulnerability lies in the absence of a capability check within the suc_submit_capabilities() function in the user_access.php file. WordPress provides functions like current_user_can() to verify that a user possesses the necessary capabilities before executing sensitive operations. The vulnerable code path fails to implement these authorization checks, creating a direct path to privilege escalation.

Attack Vector

The attack can be executed remotely over the network without requiring any authentication or user interaction. An attacker can craft malicious HTTP requests targeting the vulnerable AJAX endpoint, specifying the target user account and the desired elevated role (administrator). The lack of nonce verification or capability checks means these requests are processed without validation.

The attack scenario involves sending a crafted POST request to the WordPress AJAX handler with parameters that invoke the suc_submit_capabilities() function, specifying a target user ID and administrator role assignment. Since no authentication is required, this can be performed by any remote attacker who can reach the WordPress installation.

Detection Methods for CVE-2025-12158

Indicators of Compromise

• Unexpected user role changes, particularly elevations to administrator
• Unusual AJAX requests to admin-ajax.php containing capability or role modification parameters
• New administrator accounts appearing without authorized creation
• Unauthorized changes to site settings or content following unexplained admin access

Detection Strategies

• Monitor WordPress user role change events in audit logs for unauthorized modifications
• Implement Web Application Firewall (WAF) rules to detect and block suspicious capability modification requests
• Review access logs for unusual patterns of requests to admin-ajax.php from unauthenticated sources
• Deploy file integrity monitoring to detect unauthorized plugin or theme modifications following potential compromise

Monitoring Recommendations

• Enable comprehensive WordPress security logging to capture all user role modifications
• Configure alerts for any administrative privilege grants that occur outside normal business processes
• Implement real-time monitoring of AJAX endpoint activity for anomalous request patterns
• Regularly audit user accounts and roles to identify unauthorized privilege escalations

How to Mitigate CVE-2025-12158

Immediate Actions Required

• Deactivate and remove the Simple User Capabilities plugin immediately if version 1.0 or earlier is installed
• Audit all WordPress user accounts for unauthorized administrator role assignments
• Review site activity logs for evidence of exploitation
• Consider resetting credentials for all administrative accounts as a precaution

Patch Information

At the time of this advisory, users should check the WordPress Simple User Capabilities Plugin page for any available updates. Additional technical details and vulnerability information can be found in the Wordfence Vulnerability Report. The vulnerable code can be reviewed at the WordPress Plugin Code Review link.

Workarounds

• Remove or deactivate the Simple User Capabilities plugin until a patched version is available
• Implement WAF rules to block unauthorized requests to the suc_submit_capabilities() function endpoint
• Restrict access to the WordPress admin AJAX handler at the web server level where possible
• Consider using alternative WordPress plugins for user capability management that have proper authorization controls

# Configuration example - Remove vulnerable plugin via WP-CLI
wp plugin deactivate simple-user-capabilities --path=/var/www/html
wp plugin delete simple-user-capabilities --path=/var/www/html

# List all administrators to audit for unauthorized accounts
wp user list --role=administrator --path=/var/www/html