CVE-2026-84113: Quentn WP WordPress Plugin SQLi Vulnerability

CVE-2026-84113 Overview

CVE-2026-84113 is an authenticated SQL injection vulnerability in the Quentn WP WordPress plugin versions prior to 1.2.15. The plugin fails to properly sanitize and escape a user-supplied parameter before incorporating it into an SQL query. High-privilege users such as administrators can inject arbitrary SQL statements through the vulnerable parameter. The flaw is categorized under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command).

Critical Impact
Authenticated administrators can execute arbitrary SQL queries against the WordPress database, enabling limited confidentiality impact and potential lateral movement across multisite installations.

Affected Products

Quentn WP WordPress plugin versions prior to 1.2.15
WordPress sites with the Quentn WP integration enabled
Multisite WordPress deployments where scope change amplifies impact

Discovery Timeline

2026-09-09 - CVE-2026-84113 published to the National Vulnerability Database (NVD)
2026-09-09 - Last updated in NVD database

Technical Details for CVE-2026-84113

Vulnerability Analysis

The Quentn WP plugin exposes an administrative interface that accepts a parameter used directly in a database query. The plugin does not apply WordPress-native sanitization helpers such as esc_sql(), sanitize_text_field(), or prepared statements via $wpdb->prepare(). Attackers with administrator credentials can append or modify SQL clauses to extract data from the underlying MySQL or MariaDB database.

Exploitation requires authentication as a high-privilege user, which limits the attack surface to insider threats, compromised admin accounts, or scenarios involving credential theft. The scope change indicator suggests the vulnerable code path can impact resources beyond the plugin's immediate security context, which is relevant in WordPress multisite environments where a subsite admin may reach the network database.

Root Cause

The root cause is missing input validation and unsafe string concatenation when constructing SQL statements. The plugin trusts input from an administrative form or AJAX endpoint and passes it into a query without parameter binding. This pattern falls under CWE-89.

Attack Vector

Exploitation occurs over the network against the WordPress admin interface. An authenticated administrator submits a crafted request containing SQL metacharacters in the vulnerable parameter. The injected payload executes as part of the original query, allowing UNION-based extraction, boolean-based blind inference, or time-based blind inference depending on the query context. No user interaction is required beyond the attacker's own authenticated session.

Technical details are documented in the WPScan Vulnerability Advisory. Because verified proof-of-concept code is not published for this entry, this article intentionally omits synthetic exploit code.

Detection Methods for CVE-2026-84113

Indicators of Compromise

Administrator-issued POST or GET requests to Quentn WP endpoints containing SQL keywords such as UNION, SELECT, SLEEP(, or INFORMATION_SCHEMA
Unusual wpdb query errors or long-running queries appearing in the WordPress debug.log or MySQL slow query log
Unexpected database read operations against wp_users or wp_usermeta originating from the plugin's execution context

Detection Strategies

Review web server access logs for requests to Quentn WP administrative routes with encoded SQL metacharacters such as %27, %20UNION%20, or %20AND%20
Enable MySQL general query logging temporarily to correlate plugin activity with anomalous query structures
Deploy a web application firewall (WAF) rule set that flags SQL injection patterns targeting /wp-admin/admin.php?page=quentn* paths

Monitoring Recommendations

Baseline normal administrator query patterns and alert on deviations such as sudden spikes in query volume or new query shapes
Monitor for administrator account logins from unfamiliar IP addresses or geolocations that precede plugin configuration changes
Track file integrity of the Quentn WP plugin directory to detect tampering or malicious version rollbacks

How to Mitigate CVE-2026-84113

Immediate Actions Required

Upgrade the Quentn WP plugin to version 1.2.15 or later on all WordPress installations
Audit administrator accounts and rotate credentials for any account with recent suspicious activity
Enforce multi-factor authentication (MFA) for all WordPress administrator accounts to reduce the risk of credential misuse

Patch Information

The vendor addressed the issue in Quentn WP 1.2.15 by applying proper sanitization and parameterized queries to the affected code path. Administrators should verify the installed version via the WordPress Plugins screen or by inspecting the plugin header in quentn-wp.php. Refer to the WPScan Vulnerability Advisory for advisory-level detail.

Workarounds

Temporarily deactivate the Quentn WP plugin if immediate patching is not feasible
Restrict /wp-admin/ access by source IP allowlist at the reverse proxy or WAF layer
Apply the principle of least privilege by reducing the number of accounts assigned the administrator role

bash

# Configuration example: verify and update the Quentn WP plugin using WP-CLI
wp plugin get quentn-wp --field=version
wp plugin update quentn-wp --version=1.2.15
wp plugin status quentn-wp