CVE-2026-3056: Seraphinite Accelerator Auth Bypass Flaw

CVE-2026-3056 Overview

The Seraphinite Accelerator plugin for WordPress contains a Missing Authorization vulnerability (CWE-862) in all versions up to and including 2.28.14. The vulnerability exists due to a missing capability check on the seraph_accel_api AJAX action when the fn=LogClear function is invoked. This security flaw allows authenticated attackers with Subscriber-level access or above to clear the plugin's debug and operational logs without proper authorization.

Critical Impact

Authenticated attackers with minimal privileges (Subscriber-level) can clear plugin logs, potentially covering tracks of malicious activity or disrupting security monitoring and forensic capabilities.

Affected Products

• Seraphinite Accelerator WordPress Plugin versions ≤ 2.28.14
• WordPress installations with the vulnerable plugin versions active
• Any WordPress site allowing subscriber-level user registration with the plugin installed

Discovery Timeline

• 2026-03-04 - CVE-2026-3056 published to NVD
• 2026-03-04 - Last updated in NVD database

Technical Details for CVE-2026-3056

Vulnerability Analysis

This vulnerability is classified as Missing Authorization (CWE-862), a common security issue in WordPress plugins where AJAX endpoints fail to properly verify user capabilities before executing sensitive operations. The vulnerable code path exists within the seraph_accel_api AJAX handler, specifically when processing the LogClear function parameter.

In a properly secured WordPress plugin, AJAX actions that modify data should implement capability checks using functions like current_user_can() to ensure the requesting user has appropriate administrative privileges. The Seraphinite Accelerator plugin fails to perform this validation, allowing any authenticated user—including those with the lowest privilege level (Subscriber)—to invoke the log clearing functionality.

The attack can be carried out over the network without requiring any user interaction, making it relatively straightforward to exploit once an attacker has obtained even minimal authenticated access to the WordPress installation.

Root Cause

The root cause is the absence of a capability check in the AJAX handler processing the seraph_accel_api action with the fn=LogClear parameter. The plugin processes the request and clears logs without verifying that the requesting user has administrative or equivalent privileges. This is a classic Missing Authorization flaw where the authentication check (is the user logged in?) exists, but the authorization check (does this user have permission to perform this action?) is missing.

Attack Vector

The attack vector is network-based and requires low-privilege authentication. An attacker must first obtain authenticated access to the WordPress site, which can be achieved through:

1. Registering as a subscriber on sites with open registration enabled
2. Compromising any existing low-privilege user account
3. Exploiting other authentication vulnerabilities to gain subscriber-level access

Once authenticated, the attacker can send a crafted AJAX request to the WordPress admin-ajax.php endpoint, specifying the seraph_accel_api action with the fn=LogClear parameter. The server processes this request without proper capability verification, resulting in the deletion of plugin debug and operational logs.

The vulnerability allows attackers to manipulate the seraph_accel_api AJAX endpoint by sending a POST request to wp-admin/admin-ajax.php with the action parameter set to seraph_accel_api and the function parameter (fn) set to LogClear. Due to the missing capability check, the server accepts and processes this request from any authenticated user regardless of their role. For technical implementation details, refer to the WordPress Plugin Source Code.

Detection Methods for CVE-2026-3056

Indicators of Compromise

• Unexpected clearing of Seraphinite Accelerator plugin logs without administrator action
• AJAX requests to admin-ajax.php with action=seraph_accel_api and fn=LogClear from low-privilege users
• HTTP POST requests from subscriber-level accounts targeting the vulnerable AJAX endpoint
• Gaps or unexplained truncation in plugin operational and debug logs

Detection Strategies

• Monitor WordPress AJAX requests for the seraph_accel_api action with fn=LogClear parameter originating from non-administrator users
• Implement Web Application Firewall (WAF) rules to alert on suspicious AJAX calls to the vulnerable endpoint
• Review WordPress user activity logs for subscriber accounts making administrative-level API calls
• Deploy endpoint detection solutions to identify unauthorized log manipulation attempts

Monitoring Recommendations

• Enable comprehensive logging for WordPress AJAX requests and correlate with user role information
• Set up alerts for log file modifications or deletions in the Seraphinite Accelerator plugin directory
• Regularly audit subscriber and contributor account activity for anomalous behavior patterns
• Implement file integrity monitoring on plugin log files to detect unauthorized modifications

How to Mitigate CVE-2026-3056

Immediate Actions Required

• Update the Seraphinite Accelerator plugin to a version newer than 2.28.14 that includes the security patch
• Audit recent subscriber and low-privilege user activity for potential exploitation attempts
• Review plugin logs for signs of unauthorized clearing before updating
• Consider temporarily restricting user registration if open registration is enabled until the patch is applied

Patch Information

The vulnerability has been addressed in a newer version of the Seraphinite Accelerator plugin. The fix adds proper capability checks to the seraph_accel_api AJAX handler to ensure only users with appropriate administrative privileges can clear logs. The patch details can be reviewed in the WordPress Changeset Revision. Additional vulnerability information is available in the Wordfence Vulnerability Report.

Workarounds

• Disable the Seraphinite Accelerator plugin temporarily until the update can be applied
• Restrict WordPress user registration to prevent attackers from obtaining subscriber accounts
• Implement WAF rules to block AJAX requests with action=seraph_accel_api and fn=LogClear from non-administrator users
• Remove or demote unnecessary subscriber accounts to minimize the attack surface

# WordPress CLI command to update the plugin
wp plugin update seraphinite-accelerator

# Verify current plugin version after update
wp plugin get seraphinite-accelerator --field=version

# List all subscriber users for audit purposes
wp user list --role=subscriber --fields=ID,user_login,user_registered