CVE-2026-42416: UDesign Core SQL Injection Vulnerability

CVE-2026-42416 Overview

CVE-2026-42416 is a SQL Injection vulnerability affecting the UDesign Core WordPress plugin in versions <= 4.15.0. The flaw allows an authenticated attacker holding a low-privileged Subscriber role to inject SQL statements into database queries processed by the plugin. Successful exploitation can expose sensitive database contents and partially impact site availability. The vulnerability is categorized under CWE-89, Improper Neutralization of Special Elements used in an SQL Command.

Critical Impact
Authenticated Subscriber-level users can execute arbitrary SQL queries against the WordPress database, leading to disclosure of sensitive data stored by the site and its plugins.

Affected Products

UDesign Core WordPress plugin versions <= 4.15.0
WordPress sites that permit Subscriber-level registration with this plugin installed
Any UDesign theme deployment bundling the vulnerable core plugin

Discovery Timeline

2026-10-06 - CVE CVE-2026-42416 published to NVD
2026-10-06 - Last updated in NVD database

Technical Details for CVE-2026-42416

Vulnerability Analysis

The vulnerability resides in the UDesign Core plugin's handling of user-supplied input that is incorporated into SQL statements without adequate sanitization or parameterization. An authenticated user with Subscriber privileges can submit crafted input to a vulnerable endpoint and influence the resulting query. Because WordPress permits open user registration by default on many sites, the privilege barrier is low in practice.

The scope rating indicates the injected SQL can affect data beyond the plugin's own boundary, reaching shared WordPress tables such as wp_users and wp_usermeta. Confidentiality impact is high, while integrity is not affected and availability impact is limited. See the Patchstack SQL Injection Vulnerability advisory for additional context.

Root Cause

The root cause is improper neutralization of special characters in SQL statements [CWE-89]. The plugin concatenates attacker-controlled parameters into queries rather than using prepared statements with $wpdb->prepare(). Input validation and type casting on the relevant parameters are missing or insufficient to prevent query structure manipulation.

Attack Vector

Exploitation requires network access and valid Subscriber credentials, with no user interaction. The attacker authenticates to WordPress, then issues a crafted request to a vulnerable plugin handler. Malicious SQL fragments embedded in the request alter the executed query, enabling extraction of arbitrary rows from the database through techniques such as UNION-based or boolean-based blind injection.

No verified proof-of-concept code is published for this issue. Refer to the vendor advisory for technical details once released.

Detection Methods for CVE-2026-42416

Indicators of Compromise

Web server access logs showing authenticated Subscriber requests to UDesign Core endpoints containing SQL metacharacters such as UNION, SELECT, SLEEP(, --, or encoded variants.
Unexpected spikes in query execution time correlated with requests from low-privileged accounts.
Database error entries in debug.log referencing malformed queries originating from UDesign Core handlers.
Creation of new Administrator accounts or password hash exfiltration events tied to Subscriber sessions.

Detection Strategies

Deploy a Web Application Firewall rule set that flags SQL injection payloads in parameters sent to /wp-admin/admin-ajax.php with UDesign-related actions.
Enable WordPress query logging and alert on queries containing UNION SELECT or information_schema references originating from plugin code paths.
Correlate authentication events with high-volume database read activity from the same session identifier.

Monitoring Recommendations

Monitor plugin inventory for installations of UDesign Core at or below version 4.15.0.
Track new user registrations and watch for Subscriber accounts followed shortly by anomalous admin-ajax traffic.
Ingest WordPress and web server logs into a centralized analytics platform to run retroactive hunts for SQL injection patterns.

How to Mitigate CVE-2026-42416

Immediate Actions Required

Update the UDesign Core plugin to a version later than 4.15.0 as soon as the vendor publishes a fixed release.
Audit WordPress user accounts and remove unused or suspicious Subscriber-level accounts.
Rotate credentials and WordPress authentication salts in wp-config.php if exploitation is suspected.
Review database access logs for signs of unauthorized data extraction over the past 30 days.

Patch Information

Consult the Patchstack SQL Injection Vulnerability advisory for the fixed version and vendor remediation guidance. Apply updates through the WordPress plugin dashboard or via wp-cli.

Workarounds

Disable open user registration under Settings > General until patched to reduce the attacker pool.
Deactivate the UDesign Core plugin if the fixed version is not yet available and the site can operate without it.
Enforce a WAF rule set that blocks SQL injection payloads targeting UDesign Core admin-ajax actions.
Restrict database privileges for the WordPress database user to the minimum required set.

bash

# Configuration example
# Update UDesign Core via wp-cli once a patched version is published
wp plugin update u-design-core

# Temporarily deactivate the plugin as a workaround
wp plugin deactivate u-design-core

# Disable open user registration
wp option update users_can_register 0