CVE-2025-23736: Form To JSON Reflected XSS Vulnerability

CVE-2025-23736 Overview

CVE-2025-23736 is a Reflected Cross-Site Scripting (XSS) vulnerability affecting the WordPress Form To JSON plugin (form-to-json) developed by webgdawg. This vulnerability allows attackers to inject malicious scripts into web pages viewed by other users through improper neutralization of input during web page generation.

Reflected XSS vulnerabilities occur when user-supplied data is immediately returned by a web application and included in the response without proper sanitization. In this case, the Form To JSON plugin fails to adequately sanitize user input, enabling attackers to craft malicious URLs that execute arbitrary JavaScript in victims' browsers when clicked.

Critical Impact

Attackers can execute arbitrary JavaScript code in the context of authenticated user sessions, potentially leading to session hijacking, credential theft, or malicious actions performed on behalf of legitimate users.

Affected Products

• WordPress Form To JSON plugin version 1.0 and earlier
• All WordPress installations using the vulnerable form-to-json plugin

Discovery Timeline

• 2025-03-03 - CVE-2025-23736 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-23736

Vulnerability Analysis

This vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically as a Reflected XSS variant. The Form To JSON plugin processes user-supplied form data and converts it to JSON format, but fails to properly encode or sanitize output before rendering it back to the user.

When a victim clicks a specially crafted link containing malicious JavaScript payload, the plugin reflects this input directly into the response page without adequate filtering. The malicious script then executes within the victim's browser session with full access to the page's DOM, cookies, and session tokens.

Root Cause

The root cause of this vulnerability lies in insufficient input validation and output encoding within the Form To JSON plugin's request handling logic. The plugin directly incorporates user-controlled parameters into the HTML response without applying proper security controls such as:

• Input sanitization to strip or escape potentially dangerous characters
• Output encoding appropriate for the HTML context
• Content Security Policy headers to mitigate script execution

Attack Vector

The attack vector for this Reflected XSS vulnerability requires social engineering to succeed. An attacker must convince a victim to click a malicious link containing the XSS payload. The typical attack flow involves:

1. Attacker crafts a malicious URL targeting a vulnerable endpoint in the Form To JSON plugin
2. The URL contains JavaScript payload encoded in request parameters
3. Victim clicks the link (delivered via phishing email, social media, or other channels)
4. The vulnerable plugin reflects the malicious payload in the response
5. Victim's browser executes the attacker's JavaScript code

Since no verified code examples are available for this vulnerability, detailed technical exploitation information can be found in the Patchstack XSS Vulnerability Report.

Detection Methods for CVE-2025-23736

Indicators of Compromise

• Unusual URL patterns in web server logs containing encoded JavaScript or HTML entities in query parameters
• Requests to Form To JSON plugin endpoints with suspicious <script> tags or event handlers like onerror, onload, or onclick
• User reports of unexpected browser behavior or pop-ups when accessing forms processed by the plugin
• Security scanning tools flagging XSS patterns in plugin-related HTTP traffic

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block common XSS payload patterns in requests to WordPress plugins
• Implement server-side logging that captures full request URLs and analyze for reflected content patterns
• Use browser-based XSS detection mechanisms and Content Security Policy violation reporting
• Conduct regular vulnerability scans using tools like WPScan to identify vulnerable plugin versions

Monitoring Recommendations

• Enable detailed HTTP request logging for WordPress installations and monitor for encoded script tags
• Configure alerts for unusual patterns in referrer headers that may indicate phishing-based delivery
• Monitor Content Security Policy violation reports if CSP headers are implemented
• Review WordPress plugin audit logs for any modifications to Form To JSON configuration

How to Mitigate CVE-2025-23736

Immediate Actions Required

• Deactivate and remove the Form To JSON plugin (form-to-json) from all WordPress installations immediately
• Review web server access logs for evidence of exploitation attempts targeting the plugin
• Audit user sessions and consider forcing re-authentication for users who may have accessed malicious links
• Implement Content Security Policy headers to provide defense-in-depth against XSS attacks

Patch Information

As of the last available information, the Form To JSON plugin version 1.0 and earlier remain vulnerable. No official patch has been confirmed. Website administrators should:

1. Check for plugin updates in the WordPress admin dashboard
2. Monitor the plugin's official page for security releases
3. Review the Patchstack vulnerability report for the latest remediation guidance

Workarounds

• Disable the Form To JSON plugin until a patched version is available
• Implement a Web Application Firewall (WAF) with XSS filtering rules to block malicious requests
• Consider using alternative, actively maintained form-handling plugins with better security track records
• Add Content Security Policy headers to restrict inline script execution:

# Apache .htaccess configuration example for CSP
<IfModule mod_headers.c>
    Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'self';"
    Header set X-XSS-Protection "1; mode=block"
    Header set X-Content-Type-Options "nosniff"
</IfModule>