CVE-2026-0811: Advanced Contact Form 7 DB CSRF Vulnerability

CVE-2026-0811 Overview

The Advanced Contact form 7 DB plugin for WordPress is vulnerable to Cross-Site Request Forgery (CSRF) in all versions up to, and including, 2.0.9. This vulnerability exists due to missing or incorrect nonce validation on the vsz_cf7_save_setting_callback function. The flaw enables unauthenticated attackers to delete form entries via a forged request, provided they can trick a site administrator into performing an action such as clicking on a malicious link.

Critical Impact

Unauthenticated attackers can delete form entries by exploiting missing nonce validation, potentially resulting in data loss and integrity issues for WordPress sites using this plugin.

Affected Products

• Advanced Contact form 7 DB plugin for WordPress versions up to and including 2.0.9

Discovery Timeline

• April 8, 2026 - CVE-2026-0811 published to NVD
• April 8, 2026 - Last updated in NVD database

Technical Details for CVE-2026-0811

Vulnerability Analysis

This Cross-Site Request Forgery vulnerability arises from inadequate security controls in the plugin's administrative functionality. The vsz_cf7_save_setting_callback function fails to properly validate nonce tokens, which are designed to verify that requests originate from legitimate user interactions within the WordPress admin interface.

Without proper nonce validation, the application cannot distinguish between authentic administrative requests and forged requests submitted by an attacker. This weakness allows malicious actors to craft specialized requests that, when executed by an authenticated administrator, will perform unauthorized actions on behalf of the attacker.

Root Cause

The root cause of CVE-2026-0811 is the missing or incorrect implementation of WordPress nonce verification in the vsz_cf7_save_setting_callback function. WordPress provides the wp_verify_nonce() function specifically to prevent CSRF attacks, but this security measure was either not implemented or improperly configured in the vulnerable code path. The vulnerable code can be examined at line 885 in the plugin source code.

Attack Vector

The attack requires network access and user interaction. An attacker must craft a malicious webpage or link containing a forged request targeting the vulnerable function. When an authenticated WordPress administrator with sufficient privileges visits the attacker-controlled page or clicks the malicious link, the forged request is automatically submitted to the WordPress site. Since no valid nonce is required, the server processes the request as legitimate, resulting in the deletion of form entries.

A typical attack scenario involves:

1. Attacker identifies a WordPress site using the vulnerable plugin version
2. Attacker crafts a malicious HTML page with a hidden form or link targeting the vsz_cf7_save_setting_callback endpoint
3. Attacker tricks a site administrator into visiting the malicious page (via phishing email, compromised website, or social engineering)
4. The administrator's browser automatically submits the forged request with valid session cookies
5. Form entries are deleted without the administrator's knowledge or consent

Detection Methods for CVE-2026-0811

Indicators of Compromise

• Unexpected deletion of Contact Form 7 database entries without administrator action
• Audit logs showing administrative requests to the plugin settings endpoint from unusual referrer sources
• Reports from site administrators of missing form submission data
• HTTP requests to plugin settings callbacks originating from external domains

Detection Strategies

• Monitor WordPress audit logs for unexpected changes to Contact Form 7 DB plugin settings or data deletion events
• Implement web application firewall (WAF) rules to detect and block CSRF attack patterns targeting WordPress plugins
• Review server access logs for requests to the plugin's administrative endpoints with suspicious or missing referrer headers
• Deploy SentinelOne Singularity XDR to detect anomalous web request patterns and potential CSRF exploitation attempts

Monitoring Recommendations

• Enable comprehensive logging for WordPress administrative actions, particularly those affecting plugin data
• Configure alerts for bulk deletion operations on Contact Form 7 database entries
• Implement referrer header validation monitoring for administrative endpoints
• Establish baseline metrics for normal administrative activity to identify anomalous patterns

How to Mitigate CVE-2026-0811

Immediate Actions Required

• Update the Advanced Contact form 7 DB plugin to the latest patched version immediately
• Review Contact Form 7 database entries and restore any deleted data from backups if unauthorized deletion has occurred
• Audit plugin settings to ensure no unauthorized modifications have been made
• Educate site administrators about CSRF attack vectors and the importance of not clicking suspicious links while logged into WordPress

Patch Information

The vulnerability has been addressed in a newer version of the plugin. The fix can be reviewed in the WordPress Plugin Changeset. Users should update to the latest available version that includes proper nonce validation. Additional details about this vulnerability are available in the Wordfence Vulnerability Report.

Workarounds

• If immediate patching is not possible, restrict access to the WordPress admin area using IP-based allowlisting
• Implement additional CSRF protection at the web server or WAF level for requests to WordPress plugin endpoints
• Consider temporarily deactivating the Advanced Contact form 7 DB plugin until the update can be applied
• Use browser-based CSRF protection extensions for administrators who must access the WordPress dashboard

# Example: Restrict WordPress admin access by IP in Apache .htaccess
<Files wp-admin>
    Order deny,allow
    Deny from all
    Allow from 192.168.1.0/24
    Allow from 10.0.0.0/8
</Files>