CVE-2026-39639: RPS Include Content Auth Bypass Flaw

CVE-2026-39639 Overview

CVE-2026-39639 is a Missing Authorization vulnerability affecting the RPS Include Content WordPress plugin developed by redpixelstudios. This broken access control flaw allows attackers to exploit incorrectly configured access control security levels, potentially enabling unauthorized modifications to the WordPress site through the plugin's functionality.

The vulnerability stems from CWE-862 (Missing Authorization), indicating that the plugin fails to perform proper authorization checks before allowing certain operations. Authenticated attackers with low-level privileges can bypass intended access restrictions and perform actions they should not be permitted to execute.

Critical Impact

Authenticated users with minimal privileges can exploit missing authorization checks to perform unauthorized modifications, compromising the integrity of WordPress site content managed by the RPS Include Content plugin.

Affected Products

• RPS Include Content WordPress plugin versions up to and including 1.2.2
• WordPress installations with the rps-include-content plugin enabled
• All configurations where low-privileged users have access to the WordPress dashboard

Discovery Timeline

• 2026-04-08 - CVE-2026-39639 published to NVD
• 2026-04-09 - Last updated in NVD database

Technical Details for CVE-2026-39639

Vulnerability Analysis

This Missing Authorization vulnerability (CWE-862) in the RPS Include Content plugin allows authenticated users to bypass access control mechanisms. The plugin is designed to allow administrators to include content from various sources within WordPress pages and posts. However, the vulnerability enables users with lower privilege levels to interact with plugin functionality without proper authorization verification.

The network-based attack vector means that exploitation can occur remotely through the WordPress interface. While user interaction is not required, the attacker must have at least low-level authenticated access to the WordPress installation. The primary impact is to data integrity, as attackers can make unauthorized modifications without affecting confidentiality or availability directly.

Root Cause

The root cause of this vulnerability is the absence of proper capability checks within the RPS Include Content plugin's code paths. WordPress plugins should verify user capabilities using functions like current_user_can() before executing privileged operations. The RPS Include Content plugin fails to implement these authorization checks, allowing any authenticated user to access functionality that should be restricted to administrators or editors.

This oversight is a common issue in WordPress plugin development where developers may assume that menu visibility or page access restrictions are sufficient security controls, without implementing proper capability verification at the function level.

Attack Vector

The attack vector for CVE-2026-39639 involves an authenticated attacker with minimal WordPress privileges (such as a Subscriber or Contributor role) exploiting the missing authorization checks to perform unauthorized actions. The attack flow typically involves:

1. The attacker authenticates to the WordPress installation with a low-privilege account
2. The attacker identifies and accesses RPS Include Content plugin endpoints or AJAX handlers
3. Due to missing authorization checks, the plugin processes requests without verifying the user's capabilities
4. The attacker can modify included content configurations or access functionality intended for administrators

This vulnerability does not require user interaction from the victim, making it easily exploitable once the attacker has obtained any level of authenticated access to the WordPress site.

Detection Methods for CVE-2026-39639

Indicators of Compromise

• Unexpected changes to content inclusion settings or configurations within the RPS Include Content plugin
• WordPress audit logs showing low-privileged users accessing plugin administrative functions
• Unauthorized AJAX requests to RPS Include Content plugin endpoints from non-administrative user sessions

Detection Strategies

• Monitor WordPress activity logs for access attempts to RPS Include Content plugin settings by users without administrator capabilities
• Implement Web Application Firewall (WAF) rules to detect and block suspicious requests to the rps-include-content plugin endpoints
• Review user session activity for privilege escalation patterns or unexpected plugin interactions

Monitoring Recommendations

• Enable comprehensive WordPress audit logging to capture all plugin-related activities
• Configure alerts for any modifications to the RPS Include Content plugin settings
• Regularly review user roles and capabilities to ensure principle of least privilege

How to Mitigate CVE-2026-39639

Immediate Actions Required

• Update the RPS Include Content plugin to a patched version when available from the vendor
• Temporarily disable the rps-include-content plugin if immediate patching is not possible
• Review and audit all user accounts, removing unnecessary access for low-privilege users
• Enable WordPress security plugins to add additional access control layers

Patch Information

As of the last update, the vulnerability affects RPS Include Content versions through 1.2.2. Site administrators should monitor the Patchstack Vulnerability Report for information about patched versions. Contact redpixelstudios for updated plugin releases that address this broken access control vulnerability.

Workarounds

• Disable the RPS Include Content plugin entirely until a patch is available
• Restrict WordPress user registrations and remove accounts that do not require authenticated access
• Implement additional access control through a security plugin such as Wordfence or Sucuri to restrict plugin endpoint access
• Consider using server-level access controls to limit which users can access the WordPress admin area

# WordPress CLI command to deactivate the vulnerable plugin
wp plugin deactivate rps-include-content --path=/var/www/html/wordpress

# Verify plugin status
wp plugin status rps-include-content --path=/var/www/html/wordpress

# List all users with subscriber or contributor roles for review
wp user list --role=subscriber,contributor --fields=ID,user_login,user_email --path=/var/www/html/wordpress