CVE-2026-57687 Overview
CVE-2026-57687 is a SQL injection vulnerability affecting the WordPress Custom Field Template plugin in versions 2.7.8 and earlier. The flaw allows authenticated users with Contributor-level privileges to inject arbitrary SQL statements into database queries. The vulnerability is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command). Attackers can exploit this weakness over the network with low complexity and limited privileges, resulting in confidentiality impact on the underlying WordPress database and scope change beyond the vulnerable component.
Critical Impact
Authenticated Contributor accounts can execute arbitrary SQL queries against the WordPress database, potentially exposing sensitive data across the site.
Affected Products
- WordPress Custom Field Template plugin versions <= 2.7.8
- WordPress installations running the vulnerable plugin
- Any multi-author WordPress site granting Contributor role access
Discovery Timeline
- 2026-07-02 - CVE-2026-57687 published to NVD
- 2026-07-02 - Last updated in NVD database
Technical Details for CVE-2026-57687
Vulnerability Analysis
The Custom Field Template plugin fails to properly sanitize user-supplied input before incorporating it into SQL queries. A user holding Contributor privileges can craft input containing SQL metacharacters that alter query semantics. Because WordPress Contributor accounts are commonly granted to guest authors and freelancers, the attack surface extends beyond fully trusted users.
The scope change indicator in the CVSS vector shows that exploitation affects resources beyond the vulnerable component. In practice, a successful SQL injection against the WordPress database exposes user credentials, session tokens, and content stored across all plugins sharing the database.
Root Cause
The root cause is missing or insufficient parameterization of SQL statements built from Contributor-controlled input. Rather than using prepared statements or the WordPress $wpdb->prepare() API with correct placeholders, the plugin concatenates untrusted values into query strings. This classic [CWE-89] pattern permits attackers to break out of the intended query context.
Attack Vector
Exploitation requires network access to the WordPress site and authentication as a Contributor or higher role. The attacker submits crafted input through a plugin endpoint that reaches the vulnerable database call. No user interaction is required beyond the attacker's own request. The vulnerability manifests when the plugin processes custom field template data containing SQL injection payloads. See the Patchstack WordPress SQL Injection Advisory for additional technical detail.
Detection Methods for CVE-2026-57687
Indicators of Compromise
- Unexpected UNION SELECT, SLEEP(, or INFORMATION_SCHEMA fragments in web server access logs targeting Custom Field Template endpoints
- Anomalous database query patterns originating from wp-admin sessions belonging to Contributor accounts
- Contributor accounts issuing bulk POST requests to custom field administration URLs
Detection Strategies
- Inspect WordPress access logs for parameter values containing SQL syntax such as quotes, comments (--, #), or boolean tautologies
- Enable database query logging and correlate anomalous SELECT statements against the timing of Contributor logins
- Deploy a web application firewall with signatures for SQL injection targeting WordPress plugin endpoints
Monitoring Recommendations
- Alert on newly created or recently active Contributor accounts submitting requests to Custom Field Template administrative pages
- Monitor for privilege changes, unexpected wp_users reads, or password hash extraction attempts
- Track outbound traffic from the WordPress host for signs of data exfiltration following suspicious authenticated activity
How to Mitigate CVE-2026-57687
Immediate Actions Required
- Update the Custom Field Template plugin to a version later than 2.7.8 once released by the maintainer
- Audit all Contributor, Author, and Editor accounts and remove any that are inactive or unnecessary
- Rotate WordPress database credentials and administrator passwords if compromise is suspected
- Review the wp_users and wp_usermeta tables for unauthorized privilege changes
Patch Information
Refer to the Patchstack WordPress SQL Injection Advisory for the current patch status and fixed version details. Apply the vendor-supplied update through the WordPress plugin manager as soon as it is available.
Workarounds
- Temporarily deactivate the Custom Field Template plugin until a patched release is installed
- Restrict the Contributor role to trusted users only, or remove the role entirely on sites that do not require it
- Deploy WAF rules that block SQL injection payloads targeting admin-ajax.php and Custom Field Template endpoints
- Enforce database least privilege by ensuring the WordPress database user cannot execute FILE or administrative statements
# Configuration example: disable the plugin via WP-CLI until patched
wp plugin deactivate custom-field-template
wp user list --role=contributor --fields=ID,user_login,user_registered
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
