CVE-2026-40764: WPForms Contact Form CSRF Vulnerability

CVE-2026-40764 Overview

A Cross-Site Request Forgery (CSRF) vulnerability has been identified in the Contact Form by WPForms plugin (wpforms-lite) for WordPress, developed by Syed Balkhi. This vulnerability allows attackers to craft malicious requests that, when executed by an authenticated user, can perform unauthorized actions on behalf of that user without their knowledge or consent.

Critical Impact

Attackers can exploit this CSRF vulnerability to perform unauthorized actions by tricking authenticated WordPress administrators into clicking malicious links or visiting attacker-controlled pages, potentially leading to unauthorized form modifications, data exfiltration, or other malicious activities within the WordPress installation.

Affected Products

• Contact Form by WPForms (wpforms-lite) versions up to and including 1.10.0.2
• WordPress installations running vulnerable versions of the WPForms plugin

Discovery Timeline

• 2026-04-15 - CVE-2026-40764 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2026-40764

Vulnerability Analysis

This vulnerability falls under CWE-352 (Cross-Site Request Forgery), which occurs when a web application does not sufficiently verify that a well-formed, valid, consistent request was intentionally provided by the user who submitted the request. In the context of the WPForms plugin, certain administrative actions lack proper CSRF token validation, allowing attackers to forge requests that appear legitimate to the server.

The vulnerability is classified with a network-based attack vector, meaning exploitation can occur remotely without requiring local access to the target system. The attack complexity is high, indicating that specific conditions must be met for successful exploitation. However, no privileges are required by the attacker, and no user interaction is needed beyond the initial visit to an attacker-controlled page.

Root Cause

The root cause of this vulnerability stems from insufficient or missing CSRF token validation in the WPForms plugin. WordPress provides built-in nonce (number used once) functionality through functions like wp_nonce_field() and wp_verify_nonce() to protect against CSRF attacks. The affected versions of WPForms fail to properly implement these protections on certain form handling endpoints, leaving them susceptible to forged cross-site requests.

Attack Vector

The attack leverages the network-based vector typical of CSRF vulnerabilities. An attacker would craft a malicious HTML page or email containing hidden form elements or JavaScript that automatically submits requests to the vulnerable WPForms endpoints. When an authenticated WordPress administrator visits this malicious content, their browser automatically includes their session cookies with the forged request, causing the server to process the request as if it were legitimate.

The attack could be delivered through various methods including phishing emails with malicious links, compromised websites with hidden iframes, or social engineering tactics that convince administrators to visit attacker-controlled pages while logged into their WordPress dashboard.

Detection Methods for CVE-2026-40764

Indicators of Compromise

• Unexpected changes to WPForms configuration or form settings without administrator action
• Unusual form submissions or modifications in WordPress audit logs
• Referrer headers in web server logs showing requests to WPForms endpoints originating from external domains
• Reports from users about forms behaving unexpectedly or displaying modified content

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block CSRF attack patterns targeting WordPress plugins
• Monitor WordPress admin action logs for form modifications that lack corresponding legitimate admin sessions
• Configure server-side logging to capture and alert on suspicious referrer patterns for administrative endpoints
• Deploy endpoint detection solutions that can identify malicious redirects and hidden form submissions in browser traffic

Monitoring Recommendations

• Enable comprehensive WordPress activity logging including all form-related administrative actions
• Configure alerts for administrative actions performed outside of normal business hours or from unusual IP addresses
• Implement Content Security Policy (CSP) headers to help prevent unauthorized cross-origin requests
• Regularly audit WPForms plugin settings and compare against known-good configurations

How to Mitigate CVE-2026-40764

Immediate Actions Required

• Update the WPForms plugin (wpforms-lite) to the latest version that addresses this vulnerability
• Audit all forms and plugin configurations for unauthorized changes that may have occurred prior to patching
• Implement additional security layers such as Web Application Firewalls with CSRF protection rules
• Educate WordPress administrators about the risks of clicking links while logged into the admin dashboard

Patch Information

Users should update to the latest version of the Contact Form by WPForms plugin that addresses this CSRF vulnerability. Detailed patch information is available through the Patchstack Vulnerability Report. Always verify plugin updates through the official WordPress plugin repository to ensure authenticity.

Workarounds

• Implement a Web Application Firewall (WAF) with CSRF protection capabilities as an additional security layer
• Configure browser-based security extensions that block cross-origin requests for administrative sessions
• Limit administrator access to WordPress dashboard from trusted IP addresses only
• Use separate browser profiles or sessions for WordPress administration versus general web browsing
• Consider temporarily disabling the WPForms plugin if immediate patching is not possible and forms are not critical

# WordPress CLI command to check current WPForms version
wp plugin list --name=wpforms-lite --fields=name,version,status

# Update WPForms to latest version via WP-CLI
wp plugin update wpforms-lite

# Verify the update was successful
wp plugin list --name=wpforms-lite --fields=name,version,update_version