CVE-2026-24987: WP System Log Auth Bypass Vulnerability

CVE-2026-24987 Overview

CVE-2026-24987 is a Missing Authorization vulnerability affecting the WP System Log plugin (winterlock) developed by activity-log.com. This security flaw allows attackers to exploit incorrectly configured access control security levels, potentially enabling unauthorized users to perform actions they should not have permission to execute. The vulnerability falls under CWE-862 (Missing Authorization), indicating that the application fails to properly verify that users are authorized to access specific functionality.

Critical Impact

Authenticated attackers with low-level privileges can bypass authorization controls to modify data or perform unauthorized actions within WordPress environments running the vulnerable plugin.

Affected Products

• WP System Log plugin versions through 1.2.7
• WordPress installations running the winterlock plugin
• activity-log.com WP System Log all versions up to and including 1.2.7

Discovery Timeline

• 2026-03-25 - CVE CVE-2026-24987 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-24987

Vulnerability Analysis

This vulnerability stems from a broken access control implementation in the WP System Log plugin. The flaw allows authenticated users with minimal privileges to bypass authorization checks and perform actions that should be restricted to administrators or higher-privileged users. The vulnerability requires network access and low-level authentication, making it exploitable by any authenticated user on the WordPress site. While confidentiality remains unaffected, the integrity impact is significant as attackers can modify system data without proper authorization.

Root Cause

The root cause is classified as CWE-862: Missing Authorization. The WP System Log plugin fails to implement proper authorization checks on sensitive functionality. When users access certain features or endpoints, the application does not verify whether the authenticated user has the appropriate permissions to perform the requested action. This oversight allows lower-privileged users to access and modify resources that should be protected by role-based access controls inherent to WordPress's capability system.

Attack Vector

The attack vector is network-based, requiring an authenticated session with low privileges. An attacker who has any level of authenticated access to the WordPress installation (such as a subscriber or contributor role) can exploit this vulnerability. The attack does not require user interaction and can be executed directly against the vulnerable endpoints. The attacker leverages the missing authorization checks to escalate their effective permissions within the plugin's functionality, enabling them to perform administrative actions on logging data or system configurations managed by the plugin.

The vulnerability allows exploitation of incorrectly configured access control security levels, meaning attackers can manipulate or access log entries and system information that should be restricted to administrators. This could enable malicious users to cover their tracks by modifying logs or gain insight into system operations they should not have visibility into.

Detection Methods for CVE-2026-24987

Indicators of Compromise

• Unexpected modifications to system log entries by non-administrative users
• Unusual access patterns to WP System Log plugin endpoints from low-privileged accounts
• Audit logs showing subscriber or contributor roles accessing administrative plugin functions
• Changes to logging configurations without corresponding administrator activity

Detection Strategies

• Implement WordPress activity monitoring to track plugin function calls and correlate them with user roles
• Deploy web application firewall (WAF) rules to detect and alert on unauthorized access attempts to the winterlock plugin endpoints
• Enable detailed access logging on the WordPress server to capture all requests to plugin-specific URLs
• Regularly review user activity logs for permission anomalies and unexpected privilege usage

Monitoring Recommendations

• Monitor WordPress user sessions for actions inconsistent with assigned role capabilities
• Set up alerts for any non-administrator access to WP System Log administrative functions
• Implement real-time log analysis to detect unauthorized log modifications or deletions
• Review server access logs for patterns indicating systematic probing of plugin endpoints

How to Mitigate CVE-2026-24987

Immediate Actions Required

• Update WP System Log plugin to the latest version that addresses CVE-2026-24987
• Audit all user accounts on affected WordPress installations and review privilege assignments
• Temporarily disable the WP System Log plugin if an immediate update is not available
• Review recent system log modifications for signs of unauthorized access

Patch Information

Administrators should check for updates to the WP System Log plugin through the WordPress plugin repository or directly from activity-log.com. Detailed vulnerability information and remediation guidance is available through the Patchstack WordPress Vulnerability Database. Users running version 1.2.7 or earlier should upgrade immediately once a patched version becomes available.

Workarounds

• Restrict access to the WordPress admin panel to trusted IP addresses only until the plugin can be updated
• Remove or deactivate the WP System Log plugin if it is not critical to operations
• Implement additional access controls at the server level using .htaccess rules to restrict plugin endpoint access
• Consider using a security plugin to add capability checks for plugin functionality as a temporary measure

# Example .htaccess rule to restrict plugin access to administrators
# Place in wp-content/plugins/winterlock/ directory
<Files "*.php">
    Order Deny,Allow
    Deny from all
    # Allow only authenticated admin requests through WordPress
</Files>