CVE-2025-31080 Overview
CVE-2025-31080 is a stored Cross-Site Scripting (XSS) vulnerability in the Link Software LLC HTML Forms plugin for WordPress. The flaw affects all plugin versions up to and including 1.5.1. Attackers can inject persistent JavaScript payloads that execute in the browsers of users who view the affected pages. The vulnerability is classified under [CWE-79], improper neutralization of input during web page generation. Exploitation requires user interaction but no authentication, and the impact crosses a security boundary, allowing attackers to influence content outside the vulnerable component's scope.
Critical Impact
Unauthenticated attackers can store malicious scripts that execute in administrator and visitor browsers, enabling session theft, credential harvesting, and unauthorized administrative actions on WordPress sites running HTML Forms ≤ 1.5.1.
Affected Products
- Link Software LLC HTML Forms plugin for WordPress, versions up to and including 1.5.1
- WordPress sites with the HTML Forms plugin installed and active
- All deployments where untrusted users can submit form input rendered to other users
Discovery Timeline
- 2025-04-01 - CVE-2025-31080 published to NVD
- 2026-04-23 - Last updated in NVD database
Technical Details for CVE-2025-31080
Vulnerability Analysis
The HTML Forms plugin fails to properly neutralize user-supplied input before rendering it in generated web pages. An attacker can submit input containing HTML or JavaScript through a vulnerable form interface. The plugin stores this input and later returns it to other users without adequate output encoding or sanitization. When a victim loads the page containing the stored payload, the script executes within the victim's browser session under the site's origin.
Stored XSS in WordPress plugins typically targets administrators viewing form submissions in the admin dashboard. Successful execution in an authenticated admin context can lead to account takeover, plugin or theme modification, and persistent backdoor installation. The scope change indicates the injected script can affect resources beyond the vulnerable component itself.
Root Cause
The root cause is missing or insufficient input sanitization and output escaping in the rendering paths that display form-related data. WordPress provides functions such as esc_html(), esc_attr(), and wp_kses() for safe output, but these were not applied consistently to the affected fields in HTML Forms ≤ 1.5.1.
Attack Vector
The attack proceeds over the network. An attacker submits crafted input containing a JavaScript payload through a form or interface exposed by the plugin. The malicious content persists in the WordPress database. When an administrator or another user opens the page that renders the stored value, the browser executes the payload in the context of the WordPress site.
The vulnerability mechanism is documented in the Patchstack WordPress Vulnerability Report. No verified public exploit code is currently available.
Detection Methods for CVE-2025-31080
Indicators of Compromise
- Form submissions containing <script> tags, javascript: URIs, or HTML event handlers such as onerror, onload, or onclick
- Unexpected outbound requests from administrator browsers to external domains shortly after viewing form data
- New or modified WordPress administrator accounts following access to plugin pages
Detection Strategies
- Inspect database entries created by the HTML Forms plugin for stored HTML or JavaScript markup
- Review web server access logs for POST requests to HTML Forms endpoints carrying script-like payloads
- Use a web application firewall (WAF) with signatures for stored XSS patterns targeting WordPress plugin endpoints
Monitoring Recommendations
- Monitor WordPress installations for plugin versions matching HTML Forms ≤ 1.5.1
- Alert on administrator session anomalies, including unexpected privilege changes or content edits
- Track Content Security Policy (CSP) violation reports for blocked inline script execution
How to Mitigate CVE-2025-31080
Immediate Actions Required
- Update the HTML Forms plugin to a version newer than 1.5.1 once the vendor publishes a patched release
- If no fix is available, deactivate and remove the HTML Forms plugin from production WordPress sites
- Audit existing form submissions and database entries for previously injected payloads and remove them
Patch Information
The vendor patch status for versions newer than 1.5.1 should be verified directly with Link Software LLC and through the Patchstack advisory. Apply the fixed version once published, then validate that all stored data is re-rendered with proper escaping.
Workarounds
- Deploy a WAF rule to block requests containing script tags or event handler attributes targeting the plugin's submission endpoints
- Restrict access to form submission interfaces to authenticated, trusted users where business requirements allow
- Enforce a strict Content Security Policy that disallows inline scripts and limits script sources to trusted origins
# Example restrictive Content-Security-Policy header for WordPress
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
