CVE-2025-11977 Overview
CVE-2025-11977 is a Local File Inclusion (LFI) vulnerability in the Happyforms – Form Builder plugin for WordPress. The flaw affects all plugin versions up to and including 1.26.12 and resides in the happyforms_get_form_partial() function. Authenticated attackers with Administrator-level access or above can include and execute arbitrary .php files present on the server. Successful exploitation allows execution of any PHP code contained in those files, enabling bypass of access controls, disclosure of sensitive data, or full code execution when combined with a file upload primitive that permits .php types. The vulnerability is tracked under [CWE-98] (Improper Control of Filename for Include/Require Statement in PHP Program).
Critical Impact
Authenticated administrators can execute arbitrary PHP code on the underlying WordPress host, potentially leading to full site compromise.
Affected Products
- Happyforms – Form Builder for WordPress: Drag & Drop Contact Forms, Surveys, Payments & Multipurpose Forms plugin
- All versions up to and including 1.26.12
- WordPress installations with the affected plugin activated
Discovery Timeline
- 2026-07-10 - CVE-2025-11977 published to NVD
- 2026-07-10 - Last updated in NVD database
Technical Details for CVE-2025-11977
Vulnerability Analysis
The vulnerability exists in the happyforms_get_form_partial() function, which loads PHP template partials without sufficiently validating or restricting the supplied filename parameter. Because the function is reachable by authenticated users with Administrator privileges, an attacker able to authenticate at that level can control the file path passed to a PHP include/require call. The plugin then executes any PHP code found in the referenced file within the context of the WordPress process.
While Administrator credentials are required, the impact is significant: exploitation results in arbitrary PHP code execution beyond what standard admin functionality is intended to allow. This is particularly relevant in multi-admin environments, managed hosting scenarios, or cases where lower-trust roles have been elevated. It also becomes a stepping stone from a compromised admin account to persistent server-side code execution.
Root Cause
The root cause is improper control of a filename used in a PHP include statement [CWE-98]. The happyforms_get_form_partial() helper does not enforce a strict allow-list of template files or normalize the input against directory traversal sequences prior to inclusion.
Attack Vector
The attack vector is network-based over standard WordPress administrative HTTP requests. An authenticated administrator sends a crafted request that reaches the vulnerable partial-loading code path and specifies a path pointing to an existing .php file on the filesystem. When combined with a plugin or theme upload feature that accepts .php content, the flaw can be escalated to full remote code execution.
No verified public exploit code is available. Technical context is documented in the Wordfence Vulnerability Report and the plugin source files class-wp-customize-form-manager.php and helper-form-templates.php.
Detection Methods for CVE-2025-11977
Indicators of Compromise
- Administrative HTTP requests containing suspicious path values such as ../, absolute filesystem paths, or references to non-Happyforms .php files being passed to Happyforms endpoints.
- Unexpected PHP file executions logged by the web server originating from Happyforms template loading code paths.
- New or modified .php files under wp-content/uploads/ shortly followed by requests that reference those paths.
Detection Strategies
- Inspect WordPress and web server access logs for POST or admin-ajax requests invoking Happyforms actions with file, template, or partial parameters containing traversal characters or unexpected paths.
- Monitor for privileged WordPress user activity that deviates from established administrator baselines, particularly around plugin configuration screens.
- Correlate media library uploads of files with double extensions or unusual MIME types with subsequent Happyforms partial-loading requests.
Monitoring Recommendations
- Enable PHP open_basedir restrictions and log any violations, which often indicate LFI probing.
- Alert on file integrity changes across the WordPress installation, especially newly created .php files outside expected plugin and theme directories.
- Track administrator session creation, source IPs, and user-agent anomalies to identify compromised admin credentials leveraged for LFI exploitation.
How to Mitigate CVE-2025-11977
Immediate Actions Required
- Update the Happyforms plugin to a version later than 1.26.12 that includes the fix referenced in the WordPress plugin changeset.
- Audit all WordPress Administrator accounts and remove or downgrade any that are unnecessary; enforce strong, unique passwords and multi-factor authentication.
- Review web server and WordPress logs for evidence of prior exploitation before applying the update.
Patch Information
The vendor addressed the issue in a subsequent release of the Happyforms plugin. The code fix is documented in the WordPress HappyForms Change Log. Site operators should apply the update through the WordPress plugin management interface or via WP-CLI.
Workarounds
- Temporarily deactivate the Happyforms plugin until the patched version can be installed.
- Restrict administrative access to trusted IP ranges using web server ACLs or a web application firewall.
- Disable PHP execution in the wp-content/uploads/ directory to reduce the impact of any .php file uploaded and subsequently included.
# Disable PHP execution in the WordPress uploads directory (Apache)
cat > /var/www/html/wp-content/uploads/.htaccess <<'EOF'
<FilesMatch "\.(php|phtml|php7|phar)$">
Require all denied
</FilesMatch>
EOF
# Update the Happyforms plugin using WP-CLI
wp plugin update happyforms
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
