CVE-2026-9843 Overview
CVE-2026-9843 is an arbitrary file deletion vulnerability in the Database for Contact Form 7, WPforms, Elementor forms plugin for WordPress. The flaw affects all versions up to and including 1.5.1 and stems from insufficient file path validation in the view_page function. Unauthenticated attackers can submit poisoned form entries that, when later viewed or edited by an administrator, trigger deletion of arbitrary files on the server. Deleting sensitive files such as wp-config.php can lead to remote code execution by forcing WordPress into a setup state. The weakness is classified as a Path Traversal issue under [CWE-22].
Critical Impact
Arbitrary file deletion by unauthenticated attackers can result in remote code execution when wp-config.php or other critical PHP files are removed.
Affected Products
- Database for Contact Form 7, WPforms, Elementor forms plugin for WordPress
- All versions up to and including 1.5.1
- WordPress sites using the contact-form-entries plugin
Discovery Timeline
- 2026-06-20 - CVE-2026-9843 published to NVD
- 2026-06-22 - Last updated in NVD database
Technical Details for CVE-2026-9843
Vulnerability Analysis
The plugin stores form submissions in the database and exposes a view_page function that renders entries for administrators. The function references file paths derived from submitted form data without validating that the resolved path stays within an allowed directory. Attackers can submit a crafted entry containing traversal sequences in a JSON key. When an administrator later opens the entry, the plugin parses the stored data and invokes a file deletion routine against the attacker-controlled path. The bug is triggered through user interaction by an administrator, but the malicious payload originates from an unauthenticated source.
Root Cause
The root cause is a path traversal weakness combined with a parser inconsistency. PHP's bracket parser reshapes the attacker-crafted JSON key during processing, which causes the reshaped key to bypass the stored-path isset check that the plugin uses as its guard. After the check passes, the unsanitized traversal-bearing path reaches the deletion call. The relevant code paths are documented in the plugin source at contact-form-entries.php and includes/data.php. See the WordPress Plugin Code Review at line 539 for the affected logic.
Attack Vector
The attack is network-based and requires no authentication. An attacker submits a form containing a crafted JSON key with ../ traversal sequences pointing to a target file such as wp-config.php. The malicious entry is stored in the database. Exploitation completes when an administrator opens the entry in the plugin's view or edit interface, at which point the deletion executes server-side. The combination of unauthenticated input and required administrator interaction yields a stored, user-interaction-triggered file deletion primitive.
No verified public exploit code is available. Technical details are described in the Wordfence Vulnerability Report and the linked plugin source references.
Detection Methods for CVE-2026-9843
Indicators of Compromise
- Form entries containing path traversal sequences such as ../ or encoded variants in JSON keys or field names.
- Unexpected deletion of WordPress core or plugin files, particularly wp-config.php, index.php, or files under wp-content/.
- WordPress site redirecting to the installation wizard, indicating a missing wp-config.php.
- Web server access logs showing anonymous POST requests to form submission endpoints followed by administrator visits to admin.php?page=contact-form-entries.
Detection Strategies
- Inspect stored form entries in the wp_cf7_entries or related plugin tables for keys containing traversal characters before administrators open them.
- Monitor file integrity for wp-config.php, plugin files, and critical WordPress system files to catch unauthorized deletions.
- Review web server logs for sequences in which unauthenticated form submissions are followed by administrative view_page requests.
Monitoring Recommendations
- Enable file integrity monitoring on the WordPress installation directory with alerting on deletion events.
- Audit administrator access to the contact form entries interface and correlate with file system events.
- Implement Web Application Firewall (WAF) rules that block traversal patterns in form submissions targeting the plugin's endpoints.
How to Mitigate CVE-2026-9843
Immediate Actions Required
- Update the Database for Contact Form 7, WPforms, Elementor forms plugin to a version newer than 1.5.1 that includes the fix from changeset 3578556.
- Until patched, disable or deactivate the plugin to prevent administrators from triggering the deletion logic.
- Back up wp-config.php and other critical files so they can be restored if deletion has already occurred.
- Review stored form entries for traversal payloads and purge suspicious records before opening them in the admin UI.
Patch Information
The vendor addressed the issue in the plugin update tracked by WordPress Plugin Change Log changeset 3578556. The fix introduces stricter validation of file paths derived from stored entries. Site operators should apply the update through the WordPress plugin manager and verify the installed version is greater than 1.5.1.
Workarounds
- Deactivate the contact-form-entries plugin until the update is applied.
- Restrict administrative access to the form entries page using role-based controls or IP allowlists.
- Deploy WAF rules that reject form submissions containing ../, ..\, or URL-encoded traversal sequences in JSON keys.
- Run the WordPress directory on a filesystem mount where the web server user lacks delete permissions on wp-config.php.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
