CVE-2026-54185: Cornerstone SQL Injection Vulnerability

CVE-2026-54185 Overview

CVE-2026-54185 is a SQL injection vulnerability [CWE-89] affecting the Cornerstone WordPress plugin in versions prior to 7.8.8. The flaw allows authenticated users with Subscriber-level privileges to inject SQL statements into backend database queries. Because Subscriber is the lowest privilege role available on most WordPress sites with open registration, the barrier to exploitation is low. The vulnerability has a scope change component, meaning successful exploitation can affect resources beyond the vulnerable component itself.

Critical Impact
Authenticated attackers holding only a Subscriber account can extract sensitive database contents and degrade availability of WordPress sites running vulnerable Cornerstone plugin versions.

Affected Products

Cornerstone WordPress plugin versions prior to 7.8.8
WordPress sites with the Cornerstone page builder installed and active
WordPress installations permitting Subscriber-level registration

Discovery Timeline

2026-06-17 - CVE CVE-2026-54185 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-54185

Vulnerability Analysis

The vulnerability resides in the Cornerstone plugin, a page builder distributed for WordPress sites. User-supplied input reaches a SQL query without sufficient sanitization or parameterization. An attacker authenticated as a Subscriber can submit crafted input through a plugin endpoint accessible to low-privilege users.

The Common Weakness Enumeration classification [CWE-89] indicates improper neutralization of special elements used in an SQL command. The scope change attribute signals that the injected query can affect data or functionality outside the plugin's own boundary, including the broader WordPress database containing user credentials, session tokens, and post content.

The impact profile emphasizes confidentiality loss with partial availability impact. Integrity is not directly affected, suggesting the injection point favors data extraction over arbitrary write operations.

Root Cause

The root cause is improper neutralization of user-controlled input in SQL statements executed by the Cornerstone plugin. The plugin concatenates or interpolates request parameters into queries instead of using prepared statements with bound parameters via the WordPress $wpdb->prepare() API.

Attack Vector

The attack is delivered over the network against a WordPress site running the vulnerable Cornerstone version. The attacker authenticates with any Subscriber account, then issues a crafted HTTP request to a plugin endpoint that funnels input into a SQL query. The exploit requires no user interaction and no elevated privileges beyond the default Subscriber role.

For technical specifics, see the Patchstack Vulnerability Report.

Detection Methods for CVE-2026-54185

Indicators of Compromise

Unexpected SQL syntax fragments such as UNION SELECT, SLEEP(, or INFORMATION_SCHEMA appearing in HTTP POST or GET parameters to Cornerstone plugin endpoints under /wp-admin/admin-ajax.php or /wp-json/cornerstone/
Authenticated requests from low-privilege accounts targeting Cornerstone AJAX actions at unusual rates
Database error messages or unusually long response times correlated with Cornerstone-related requests in web server logs

Detection Strategies

Inspect WordPress access logs for requests to Cornerstone endpoints originating from accounts assigned the subscriber role
Deploy a Web Application Firewall ruleset that flags SQL meta-characters and boolean payloads in plugin request parameters
Correlate authentication events for newly registered Subscriber accounts with subsequent plugin endpoint activity

Monitoring Recommendations

Enable WordPress query logging or a database activity monitor to capture queries originating from plugin code paths
Alert on response time anomalies indicative of time-based blind SQL injection probing
Track creation of new Subscriber accounts followed by plugin endpoint access within short time windows

How to Mitigate CVE-2026-54185

Immediate Actions Required

Update the Cornerstone plugin to version 7.8.8 or later on all WordPress installations
Audit existing Subscriber accounts and remove any that are not legitimately required
Temporarily disable open user registration in WordPress settings until the patch is applied

Patch Information

The vendor has released Cornerstone version 7.8.8, which remediates the SQL injection by introducing proper input sanitization and parameterized queries. Site administrators should apply this update through the WordPress plugin manager or via WP-CLI. Refer to the Patchstack Vulnerability Report for advisory details.

Workarounds

Restrict access to Cornerstone AJAX and REST endpoints at the web server or WAF layer until the plugin is patched
Disable the Cornerstone plugin entirely if the page builder is not actively in use
Set users_can_register to false in WordPress general settings to prevent unauthenticated actors from obtaining Subscriber credentials

bash

# Update Cornerstone via WP-CLI
wp plugin update cornerstone --version=7.8.8

# Verify installed version
wp plugin get cornerstone --field=version

# Disable open registration as a temporary workaround
wp option update users_can_register 0