CVE-2024-11052 Overview
CVE-2024-11052 is a Stored Cross-Site Scripting (XSS) vulnerability in the Ninja Forms – The Contact Form Builder That Grows With You plugin for WordPress. The flaw affects all versions up to and including 3.8.19. It stems from insufficient input sanitization and output escaping on the calculations parameter. Unauthenticated attackers can inject arbitrary web scripts that execute in the browser of any user who visits an affected page. The vulnerability is tracked under CWE-79: Improper Neutralization of Input During Web Page Generation.
Critical Impact
Unauthenticated attackers can persistently inject JavaScript into WordPress pages rendering Ninja Forms, enabling session theft, credential harvesting, and administrative account takeover when a privileged user views the affected page.
Affected Products
- Ninja Forms plugin for WordPress — all versions up to and including 3.8.19
- WordPress sites using the vulnerable Calculations.php metabox handler
- Any WordPress deployment where the Ninja Forms plugin is active and reachable
Discovery Timeline
- 2024-12-12 - CVE-2024-11052 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-11052
Vulnerability Analysis
The vulnerability resides in the Ninja Forms plugin's handling of the calculations parameter processed by the Calculations.php metabox. The plugin fails to sanitize input on write and does not escape output on render. As a result, attacker-supplied JavaScript payloads stored through the calculations parameter persist in the database and execute in the browser context of any user who loads the affected page.
Because the exploit requires user interaction to trigger the injected script and can affect content outside the vulnerable component's scope, the impact extends across the WordPress site. Successful exploitation allows session cookie theft, forced administrative actions via CSRF chaining, credential harvesting through injected forms, and redirection to attacker-controlled infrastructure.
Root Cause
The root cause is a missing sanitization step on data written through the calculations parameter and a missing escaping step when that data is rendered back to the DOM. The vulnerable code path is located in the plugin file includes/Admin/Metaboxes/Calculations.php at line 26, referenced in the WordPress Ninja Forms plugin source. WordPress provides helpers such as sanitize_text_field() and esc_html() for exactly this scenario, but neither was applied to the affected parameter.
Attack Vector
The attack is network-reachable and requires no authentication. An attacker submits a crafted request containing a malicious payload in the calculations parameter. The payload is stored server-side and later rendered without escaping. When a legitimate user — including a site administrator — loads a page that renders the stored value, the injected script executes in their browser session. Additional technical detail is available in the Wordfence vulnerability report.
Detection Methods for CVE-2024-11052
Indicators of Compromise
- Ninja Forms form definitions or calculation fields containing <script>, onerror=, onload=, or javascript: payloads in the database
- Unexpected outbound requests from browsers loading pages containing Ninja Forms
- New or modified WordPress administrator accounts created after suspicious form edits
- Anomalous POST requests to WordPress admin-ajax or REST endpoints referencing calculations
Detection Strategies
- Query the wp_posts and wp_postmeta tables for Ninja Forms entries containing HTML event handlers or <script> tags in calculation fields
- Inspect web server logs for unauthenticated POST requests submitting calculations parameter values with encoded script content
- Monitor Content Security Policy (CSP) violation reports for inline script execution on pages that host Ninja Forms
Monitoring Recommendations
- Enable WordPress audit logging for form definition changes and plugin option updates
- Alert on Ninja Forms plugin versions at or below 3.8.19 reported by asset inventory
- Correlate browser telemetry with WordPress request logs to identify script execution originating from stored form content
How to Mitigate CVE-2024-11052
Immediate Actions Required
- Upgrade Ninja Forms to a version later than 3.8.19 on every WordPress site in the environment
- Audit existing Ninja Forms configurations for injected script payloads and remove any malicious content
- Rotate WordPress administrator credentials and invalidate active sessions if evidence of exploitation exists
- Restrict access to the WordPress admin interface via IP allowlists or an authenticated reverse proxy
Patch Information
The vendor addressed the flaw in a Ninja Forms release subsequent to 3.8.19. Confirm the fixed version in the Wordfence vulnerability report and upgrade through the WordPress plugin manager or WP-CLI. Verify the installed version matches the patched release after upgrading.
Workarounds
- Deactivate the Ninja Forms plugin until the patched version can be deployed
- Deploy a Web Application Firewall (WAF) rule blocking requests containing script tags or JavaScript event handlers in the calculations parameter
- Enforce a strict Content Security Policy that disallows inline scripts on pages hosting Ninja Forms
# Upgrade Ninja Forms using WP-CLI
wp plugin update ninja-forms
# Verify installed version is greater than 3.8.19
wp plugin get ninja-forms --field=version
# If patching is not immediately possible, deactivate the plugin
wp plugin deactivate ninja-forms
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
