CVE-2026-25366: Woody Ad Snippets RCE Vulnerability

CVE-2026-25366 Overview

CVE-2026-25366 is a critical Code Injection vulnerability affecting the Themeisle Woody ad snippets (insert-php) WordPress plugin. This vulnerability allows authenticated attackers to inject and execute arbitrary code on vulnerable WordPress installations. The flaw stems from improper control of code generation, classified under CWE-94 (Improper Control of Generation of Code).

The Woody ad snippets plugin enables WordPress administrators to insert PHP code snippets directly into posts, pages, and widgets. However, due to insufficient access controls and input validation, lower-privileged authenticated users can exploit this functionality to execute arbitrary PHP code on the server.

Critical Impact
Authenticated attackers can achieve Remote Code Execution (RCE) on affected WordPress installations, potentially leading to complete site compromise, data exfiltration, and lateral movement within the hosting environment.

Affected Products

Woody ad snippets (insert-php) plugin versions through 2.7.1
WordPress installations using vulnerable versions of the insert-php plugin
Themeisle Woody ad snippets plugin (all versions up to and including 2.7.1)

Discovery Timeline

2026-03-25 - CVE-2026-25366 published to NVD
2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-25366

Vulnerability Analysis

This Code Injection vulnerability exists in the Woody ad snippets WordPress plugin, which is designed to allow administrators to embed PHP code within WordPress content. The vulnerability arises from inadequate authorization checks when processing PHP code snippets, allowing users with lower privilege levels than intended to create and execute arbitrary PHP code.

When a user submits a request to create or modify a code snippet, the plugin fails to properly validate the user's capabilities and permissions. This oversight allows authenticated users with minimal privileges (such as subscribers or contributors) to inject malicious PHP code that will be executed on the server when the snippet is rendered.

The scope change indicated in the vulnerability metrics means that exploitation can affect resources beyond the vulnerable component itself, potentially compromising the entire WordPress installation, the database, and potentially other sites on shared hosting environments.

Root Cause

The root cause of CVE-2026-25366 lies in improper access control implementation within the plugin's code snippet handling functionality. The plugin does not adequately verify that the authenticated user has appropriate administrative privileges before allowing PHP code to be saved and executed. This allows authenticated users with minimal permissions to bypass intended security restrictions and achieve code execution with the privileges of the web server process.

Attack Vector

The attack vector for this vulnerability is network-based and requires authentication. An attacker with a valid WordPress account (even with minimal privileges such as subscriber role) can exploit this vulnerability by crafting malicious requests to the plugin's endpoints. The attack requires no user interaction and can be executed remotely.

The exploitation flow typically involves:

Authenticating to the WordPress installation with any valid user account
Submitting a crafted request to create a PHP code snippet containing malicious code
Triggering the execution of the snippet through normal page rendering or direct access

Due to the nature of PHP code execution, successful exploitation can lead to complete server compromise, including the ability to read/write files, execute system commands, access the database, and establish persistent backdoors.

For technical details on exploitation, see the Patchstack vulnerability advisory.

Detection Methods for CVE-2026-25366

Indicators of Compromise

Unexpected PHP code snippets created in the Woody ad snippets plugin by non-administrator users
Web server logs showing unusual POST requests to plugin endpoints from authenticated sessions
Presence of suspicious PHP files or webshells in the WordPress installation directory
Unexpected outbound network connections from the web server process

Detection Strategies

Monitor WordPress audit logs for snippet creation or modification events by users without administrative privileges
Implement file integrity monitoring on WordPress core files and plugin directories to detect unauthorized modifications
Review web application firewall (WAF) logs for PHP code patterns in request bodies to plugin endpoints
Deploy runtime application self-protection (RASP) solutions to detect and block code injection attempts

Monitoring Recommendations

Enable comprehensive WordPress activity logging using security plugins to track all snippet-related actions
Configure alerts for any user account permission escalations or unusual authentication patterns
Implement database query monitoring to detect unauthorized data access or exfiltration attempts
Monitor system process execution to identify any commands spawned by the web server user

How to Mitigate CVE-2026-25366

Immediate Actions Required

Update the Woody ad snippets (insert-php) plugin to a patched version immediately if available
Audit all existing code snippets in the plugin for unauthorized or malicious content
Review user accounts and revoke unnecessary privileges, especially for subscriber and contributor roles
Consider temporarily deactivating the plugin until a patch is applied

Patch Information

Review the Patchstack vulnerability database for the latest information on available patches and remediation guidance. Contact Themeisle for updated plugin versions that address this vulnerability.

Workarounds

Restrict plugin access to trusted administrator accounts only through capability management plugins
Implement a Web Application Firewall (WAF) with rules to block suspicious PHP code patterns in request bodies
Disable user registration on the WordPress site if not required to prevent attacker account creation
Use file permission hardening to limit the web server's ability to write to sensitive directories

bash

# Configuration example - Restrict WordPress file permissions
# Set proper ownership and permissions on WordPress directories
find /var/www/wordpress -type d -exec chmod 755 {} \;
find /var/www/wordpress -type f -exec chmod 644 {} \;
chmod 400 /var/www/wordpress/wp-config.php