CVE-2025-31744: YouTube Embed Plugin Stored XSS Vulnerability

CVE-2025-31744 Overview

CVE-2025-31744 is a stored cross-site scripting (XSS) vulnerability in the Lightweight and Responsive Youtube Embed WordPress plugin by wpszaki. The flaw affects all versions up to and including 1.0.0. The vulnerability stems from improper neutralization of user-supplied input during web page generation, classified under [CWE-79]. An authenticated attacker with low privileges can inject persistent JavaScript payloads that execute in the browsers of users who view affected pages. The scope-changed impact allows the injected script to affect components beyond the vulnerable plugin itself.

Critical Impact

An authenticated contributor-level user can inject persistent JavaScript that executes against administrators or site visitors, enabling session theft, account takeover, and redirection to malicious infrastructure.

Affected Products

• wpszaki Lightweight and Responsive Youtube Embed plugin for WordPress
• All versions from n/a through 1.0.0
• WordPress sites running the affected plugin with contributor-level or higher user accounts

Discovery Timeline

• 2025-04-01 - CVE-2025-31744 published to the National Vulnerability Database
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-31744

Vulnerability Analysis

The vulnerability resides in how the Lightweight and Responsive Youtube Embed plugin processes and renders user-supplied data associated with YouTube embed shortcodes or configuration parameters. The plugin fails to properly sanitize input before storing it and later fails to escape the stored data when rendering it into the HTML response. This produces a stored XSS condition where injected scripts persist in the database and execute each time a victim loads an affected page.

Exploitation requires an authenticated user with permission to create or edit content that leverages the plugin. Once the payload is stored, subsequent visitors, including site administrators, trigger the payload during normal browsing. The scope change reflects that scripts executing in an administrator's session can pivot to actions well beyond the plugin, including creating new administrator accounts, installing malicious plugins, or exfiltrating session cookies.

Root Cause

The root cause is missing or insufficient output encoding of attacker-controlled input within the plugin's rendering path. Standard WordPress escaping functions such as esc_attr(), esc_html(), or wp_kses() are either absent or misapplied on values that reach the HTML output.

Attack Vector

The attack is delivered over the network and requires low privileges plus user interaction. An attacker with contributor or author access submits content containing a malicious payload through the plugin's input surface. When a privileged user views the rendered page, the browser parses and executes the injected script in the context of the WordPress origin. Consult the Patchstack Vulnerability Report for the disclosed technical detail.

Detection Methods for CVE-2025-31744

Indicators of Compromise

• Unexpected <script> tags, javascript: URIs, or event handler attributes (onerror, onload) stored in WordPress wp_posts or plugin-specific metadata tables
• Outbound HTTP requests from administrator browsers to unknown domains shortly after visiting posts using the plugin
• Creation of new administrator accounts or unexpected plugin installations following content edits
• Modified WordPress options or nonces indicating administrative actions initiated from an unusual browser context

Detection Strategies

• Query the WordPress database for post content and plugin option values matching regex patterns for script tags and inline event handlers
• Deploy a web application firewall rule set that inspects POST bodies submitted to wp-admin/post.php for XSS payload signatures
• Enable and review WordPress audit logs to identify contributor or author accounts submitting content containing HTML or script tokens

Monitoring Recommendations

• Monitor endpoint telemetry for administrator browser processes making anomalous outbound connections after WordPress logins
• Alert on new WordPress user creation events with administrator role assignment outside of change windows
• Track plugin version inventory across managed WordPress instances to flag any host still running lightweight-and-responsive-youtube-embed version 1.0.0 or earlier

How to Mitigate CVE-2025-31744

Immediate Actions Required

• Deactivate and remove the Lightweight and Responsive Youtube Embed plugin until a patched release is confirmed available from the vendor
• Audit all contributor, author, and editor accounts and remove or reset any that are unnecessary or dormant
• Scan existing posts, pages, and plugin option tables for stored script payloads and purge malicious content
• Rotate WordPress administrator credentials and invalidate active sessions if compromise is suspected

Patch Information

As of publication, the advisory indicates the vulnerability affects versions up to and including 1.0.0 with no fixed version identified in the reference data. Monitor the Patchstack Vulnerability Report and the WordPress plugin repository for updated releases.

Workarounds

• Restrict content submission privileges to trusted users only and disable self-registration for contributor roles
• Deploy a Content Security Policy (CSP) header that blocks inline scripts to reduce the impact of stored XSS payloads
• Configure a web application firewall to filter HTML tags and JavaScript event handlers from user submissions targeting plugin input fields
• Replace the plugin with an alternative YouTube embed solution that receives active security maintenance

# Example CSP header to mitigate stored XSS impact
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-src https://www.youtube.com https://www.youtube-nocookie.com;"