CVE-2026-24358: Quiz And Survey Master Auth Bypass Flaw

CVE-2026-24358 Overview

CVE-2026-24358 is a Missing Authorization vulnerability (CWE-862) affecting the Quiz And Survey Master WordPress plugin developed by ExpressTech Systems. This vulnerability allows attackers to exploit incorrectly configured access control security levels, potentially enabling unauthorized access to sensitive plugin functionality. The vulnerability is classified as Broken Access Control, which occurs when proper authorization checks are missing from privileged functionality.

Critical Impact

Unauthorized users may be able to access, modify, or delete quiz and survey data, potentially compromising site integrity and exposing sensitive user responses collected through the plugin.

Affected Products

• Quiz And Survey Master (quiz-master-next) WordPress plugin versions through 10.3.3
• WordPress installations running vulnerable versions of the plugin
• All sites using the affected plugin without additional access control measures

Discovery Timeline

• 2026-01-22 - CVE CVE-2026-24358 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2026-24358

Vulnerability Analysis

This vulnerability stems from missing authorization checks within the Quiz And Survey Master WordPress plugin. The plugin fails to properly verify user permissions before allowing access to certain administrative or privileged functions. This type of Broken Access Control vulnerability allows attackers to bypass intended security restrictions and perform actions that should require elevated privileges.

The Quiz And Survey Master plugin is widely used for creating quizzes, surveys, and other interactive content on WordPress sites. Without proper authorization enforcement, authenticated users with lower privilege levels (such as subscribers or contributors) may be able to access functionality intended only for administrators, or in some cases, unauthenticated users may gain access to protected resources.

Root Cause

The root cause of CVE-2026-24358 is the absence of proper capability checks (such as current_user_can() in WordPress) before executing sensitive operations. WordPress plugins must explicitly verify that the current user has appropriate permissions before processing requests that modify data or access restricted functionality. When these checks are omitted, the application relies solely on interface-level restrictions, which can be easily bypassed by directly accessing the underlying endpoints.

Attack Vector

An attacker can exploit this vulnerability by directly accessing plugin endpoints or AJAX handlers that lack proper authorization verification. The attack does not require sophisticated techniques—an attacker simply needs to identify the vulnerable endpoints and submit requests to them. Depending on the specific functionality exposed, this could allow:

• Accessing quiz results and user-submitted answers without authorization
• Modifying quiz configurations or questions
• Deleting quizzes, surveys, or collected responses
• Exporting sensitive user data

The vulnerability can be exploited by authenticated users with minimal privileges, and potentially by unauthenticated attackers if the affected endpoints do not require authentication at all. For technical details regarding this vulnerability, refer to the Patchstack Vulnerability Advisory.

Detection Methods for CVE-2026-24358

Indicators of Compromise

• Unexpected changes to quiz or survey configurations without corresponding administrator activity
• Missing or modified quiz responses that administrators did not alter
• Unusual access patterns to plugin-related AJAX endpoints in server logs
• User accounts with low privileges accessing administrative plugin pages

Detection Strategies

• Review WordPress access logs for requests to Quiz And Survey Master plugin endpoints from unauthorized user roles
• Monitor for AJAX requests to admin-ajax.php with qsm or quiz-master-next related actions from non-administrator sessions
• Implement WordPress audit logging plugins to track changes to quiz and survey content
• Set up alerts for bulk data exports or deletions within the plugin

Monitoring Recommendations

• Enable detailed WordPress access logging including user roles and request parameters
• Deploy a Web Application Firewall (WAF) with rules to detect unauthorized access attempts to WordPress plugin endpoints
• Regularly review user activity logs for anomalous behavior patterns
• Consider implementing additional authorization layers through security plugins

How to Mitigate CVE-2026-24358

Immediate Actions Required

• Update the Quiz And Survey Master plugin to a version newer than 10.3.3 once a patch is available
• Review user roles and remove unnecessary accounts with contributor or higher privileges
• Audit recent quiz and survey changes for signs of unauthorized modifications
• Consider temporarily disabling the plugin if it is not critical to site operations until a patch is released

Patch Information

At the time of publication, users should monitor for updates from ExpressTech Systems addressing this vulnerability. Check the WordPress plugin repository and the Patchstack Vulnerability Advisory for patch availability and update instructions.

Workarounds

• Restrict access to the WordPress admin area using IP whitelisting at the server level
• Implement a WordPress security plugin that provides additional authorization controls and capability checks
• Remove or reduce privileges for non-essential user accounts
• Use .htaccess rules to limit access to plugin directories and AJAX handlers

# Example .htaccess rule to restrict access to admin-ajax.php
# Add to WordPress root .htaccess file
<Files admin-ajax.php>
    Order Deny,Allow
    Deny from all
    Allow from 192.168.1.0/24
    # Add your trusted IP ranges above
</Files>