CVE-2026-57335: WPQuads Auth Bypass Vulnerability

CVE-2026-57335 Overview

CVE-2026-57335 is a broken access control vulnerability in the Ads by WPQuads WordPress plugin (also known as Quick AdSense Reloaded) affecting versions 3.0.3 and earlier. The flaw allows authenticated users with Subscriber-level privileges to perform actions that should be restricted to higher-privileged roles. The vulnerability is categorized under CWE-862: Missing Authorization and results from insufficient capability checks on plugin functionality.

Critical Impact
Authenticated subscribers can bypass authorization controls to modify plugin data or configuration, resulting in high integrity impact on WordPress sites running vulnerable versions of the Ads by WPQuads plugin.

Affected Products

Ads by WPQuads (Quick AdSense Reloaded) WordPress plugin versions <= 3.0.3
WordPress sites with the plugin installed and active
Sites permitting Subscriber-level account registration

Discovery Timeline

2026-06-29 - CVE-2026-57335 published to NVD
2026-07-01 - Last updated in NVD database

Technical Details for CVE-2026-57335

Vulnerability Analysis

CVE-2026-57335 stems from missing authorization checks in the Ads by WPQuads plugin. The plugin exposes functionality accessible to authenticated users without verifying whether the requesting account holds the required WordPress capability. Subscribers are the lowest-privilege authenticated role in WordPress and typically only have read capability. Any function that mutates plugin state must gate access with current_user_can() checks tied to administrative capabilities such as manage_options.

The attack vector is network-based and requires low complexity. Exploitation requires only a valid subscriber account, which is trivially obtainable on WordPress sites that allow open registration. No user interaction is needed beyond the attacker sending crafted authenticated requests. The impact profile shows high integrity damage with no direct confidentiality or availability consequences, indicating the vulnerable endpoints permit unauthorized data modification rather than data exfiltration or service disruption.

Root Cause

The root cause is missing authorization enforcement [CWE-862] on plugin AJAX handlers or admin-post actions. The vulnerable code paths verify authentication through WordPress nonces or logged-in state but omit role or capability validation. This allows any authenticated user, including subscribers, to invoke privileged operations.

Attack Vector

An attacker registers or logs into a subscriber account on a target WordPress site running Ads by WPQuads <= 3.0.3. The attacker then issues authenticated HTTP requests to the vulnerable plugin endpoints. Because capability checks are absent, the plugin processes the requests as if issued by a privileged administrator, permitting modifications to plugin configuration or advertisement data.

No verified proof-of-concept code is publicly available. Refer to the Patchstack WordPress Vulnerability Report for additional technical detail.

Detection Methods for CVE-2026-57335

Indicators of Compromise

Unexpected modifications to Ads by WPQuads plugin settings or ad configurations without corresponding administrator activity
Authenticated admin-ajax.php or admin-post.php requests originating from subscriber accounts targeting WPQuads plugin actions
New or modified advertisement entries appearing without administrator audit trail
Subscriber accounts issuing requests to plugin endpoints outside normal user workflows

Detection Strategies

Review WordPress access logs for POST requests to admin-ajax.php where the action parameter references WPQuads handlers and the authenticated user role is Subscriber
Compare plugin settings against known-good backups to identify unauthorized configuration changes
Audit newly registered subscriber accounts followed by administrative actions on ad configuration

Monitoring Recommendations

Enable WordPress audit logging plugins to capture user role, action, and endpoint for all authenticated requests
Alert on any Subscriber-role account invoking plugin AJAX actions that modify state
Monitor for anomalous request rates from newly created low-privilege accounts

How to Mitigate CVE-2026-57335

Immediate Actions Required

Update Ads by WPQuads to a version later than 3.0.3 once a patched release is confirmed by the vendor
Disable open user registration on WordPress sites where subscriber-level accounts are not required
Audit existing subscriber accounts and remove any unrecognized or unused accounts
Review plugin configuration and ad content for unauthorized changes

Patch Information

Consult the Patchstack WordPress Vulnerability Report for the latest patch availability and remediation guidance from the plugin maintainer.

Workarounds

Deactivate the Ads by WPQuads plugin until a patched version is available if the plugin is not business-critical
Restrict access to admin-ajax.php and admin-post.php for subscriber accounts using a Web Application Firewall (WAF) rule
Set WordPress users_can_register option to false to prevent unauthenticated attackers from creating subscriber accounts
Apply virtual patching rules via a WAF to block requests targeting known vulnerable WPQuads action handlers

bash

# Disable open user registration via WP-CLI
wp option update users_can_register 0

# Deactivate the vulnerable plugin as a temporary workaround
wp plugin deactivate quick-adsense-reloaded

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