CVE-2026-9187: WordPress Plugin Auth Bypass Vulnerability

CVE-2026-9187 Overview

CVE-2026-9187 affects the Abandoned Contact Form 7 plugin for WordPress in versions up to and including 2.2. The vulnerability allows unauthenticated attackers to permanently delete arbitrary posts, pages, or other content on affected sites. The flaw stems from a missing capability check and missing nonce validation in the action__remove_abandoned() function. This handler is registered to both the wp_ajax_remove_abandoned and wp_ajax_nopriv_remove_abandoned hooks, exposing it to unauthenticated requests. An attacker can trigger destructive deletion by sending a single admin-ajax.php POST request with a crafted recover_id parameter.

Critical Impact

Unauthenticated remote attackers can permanently delete arbitrary WordPress posts, pages, and custom post types, causing content loss and site disruption.

Affected Products

• Abandoned Contact Form 7 plugin for WordPress, versions up to and including 2.2
• WordPress sites with the plugin installed and activated
• Any WordPress content type stored as a post (posts, pages, media, custom post types)

Discovery Timeline

• 2026-06-16 - CVE-2026-9187 published to NVD
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-9187

Vulnerability Analysis

The vulnerability is a Missing Authorization issue classified as [CWE-862]. The action__remove_abandoned() function in inc/class.cf7af.php handles AJAX requests for removing abandoned form submissions. The function is registered to both authenticated (wp_ajax_remove_abandoned) and unauthenticated (wp_ajax_nopriv_remove_abandoned) AJAX hooks. Neither hook performs capability checks or nonce validation before executing the deletion logic.

The handler accepts a user-supplied recover_id parameter directly from $_POST and passes it to wp_delete_post() with the force-delete flag set to true. The function never verifies that the supplied ID belongs to the plugin's own cf7af_data post type. This allows the deletion of any post in the WordPress database, bypassing the trash and removing content permanently.

Root Cause

The root cause is a combination of two access control failures. First, the AJAX endpoint is exposed to unauthenticated users through the wp_ajax_nopriv_ hook without justification. Second, the handler omits both a current_user_can() capability check and a wp_verify_nonce() validation. The absence of post type validation compounds the issue by allowing the recover_id to reference any post in the database.

Attack Vector

Exploitation requires only network access to the target WordPress site's admin-ajax.php endpoint. An attacker submits a POST request specifying action=remove_abandoned and an arbitrary recover_id value corresponding to the target post ID. The server executes wp_delete_post($recover_id, true), which removes the post permanently. Attackers can enumerate post IDs sequentially or target known IDs to delete critical pages, published posts, or media library entries.

No authentication, user interaction, or special privileges are required. Refer to the Wordfence Vulnerability Analysis and the WordPress Plugin Code Snippet for the vulnerable handler implementation.

Detection Methods for CVE-2026-9187

Indicators of Compromise

• POST requests to /wp-admin/admin-ajax.php containing action=remove_abandoned from unauthenticated sessions
• Unexpected permanent deletion of posts, pages, or custom post types without a corresponding administrator action in audit logs
• Web server access logs showing repeated admin-ajax.php requests with sequential recover_id parameter values
• Missing content reported by users where the WordPress trash does not contain the deleted items

Detection Strategies

• Inspect web server and WordPress logs for admin-ajax.php traffic invoking the remove_abandoned action from anonymous clients
• Deploy a Web Application Firewall (WAF) rule to flag or block requests targeting the vulnerable action without valid authentication cookies or nonces
• Compare current post inventory against backups to identify unauthorized deletions of post, page, or attachment types

Monitoring Recommendations

• Enable WordPress activity logging plugins to track post deletion events and the originating user or IP address
• Forward web server logs to a centralized SIEM and alert on high-rate admin-ajax.php requests from a single source
• Monitor for wp_delete_post calls in application traces where the post type does not match cf7af_data

How to Mitigate CVE-2026-9187

Immediate Actions Required

• Deactivate and remove the Abandoned Contact Form 7 plugin until a patched version is released and verified
• Restrict access to /wp-admin/admin-ajax.php for the remove_abandoned action at the WAF or reverse proxy layer
• Verify recent backups of all WordPress content and confirm restoration procedures are functional
• Audit existing posts and pages for unauthorized deletions and restore content from backups where required

Patch Information

At the time of publication, no vendor-supplied patch is referenced in the available advisory data. The plugin is described as abandoned, indicating that an official fix may not be forthcoming. Site administrators should plan for permanent removal of the plugin and migration to an actively maintained alternative for Contact Form 7 submission recovery.

Workarounds

• Remove the plugin entirely if no patch is available from the maintainer
• Apply a WAF rule that blocks POST requests to admin-ajax.php with action=remove_abandoned unless a valid administrator nonce is present
• Use a custom mu-plugin to unhook the vulnerable AJAX action by calling remove_action('wp_ajax_nopriv_remove_abandoned', ...) and remove_action('wp_ajax_remove_abandoned', ...)
• Restrict access to the WordPress admin endpoints by IP allowlist where operationally feasible

# Example WAF/ModSecurity rule to block unauthenticated exploitation
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
  "chain,phase:2,deny,status:403,id:1026918701,msg:'Block CVE-2026-9187 exploitation attempt'"
  SecRule ARGS:action "@streq remove_abandoned" \
    "chain"
    SecRule &REQUEST_COOKIES:/wordpress_logged_in_/ "@eq 0"