CVE-2026-9059: NextGEN Gallery SQL Injection Vulnerability

CVE-2026-9059 Overview

CVE-2026-9059 is an authenticated SQL injection vulnerability in NextGEN Gallery versions prior to 4.2.1. The flaw resides in the REST API endpoints /imagely/v1/galleries and /imagely/v1/albums, where the orderby parameter is processed without sufficient sanitization. An authenticated attacker holding the NextGEN Gallery overview capability — granted to the Administrator role by default — can inject arbitrary SQL into the ORDER BY clause. The weakness is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command).

Critical Impact

Successful exploitation enables arbitrary SQL execution against the WordPress database, exposing credential hashes, session tokens, and sensitive site configuration data.

Affected Products

• NextGEN Gallery WordPress plugin versions prior to 4.2.1
• WordPress installations with the NextGEN Gallery overview capability assigned
• Sites exposing the /imagely/v1/galleries and /imagely/v1/albums REST endpoints

Discovery Timeline

• 2026-05-20 - CVE-2026-9059 published to NVD
• 2026-05-20 - Last updated in NVD database

Technical Details for CVE-2026-9059

Vulnerability Analysis

The vulnerability targets the REST API surface introduced by NextGEN Gallery for managing galleries and albums. Both endpoints accept an orderby query parameter that is passed to the data mapper layer responsible for building SQL queries. The _clean_column() sanitization function processes this user-controlled value before it is interpolated into the ORDER BY clause of the resulting query.

Because the ORDER BY clause cannot be safely parameterized using prepared statements, the plugin relies on sanitization rather than binding. The chosen sanitization strategy is inadequate, allowing crafted payloads to escape the intended column-name context and append attacker-controlled SQL.

Root Cause

The defect stems from _clean_column() implementing a character blacklist rather than a strict whitelist. A blacklist enumerates forbidden characters and removes them, but any character not explicitly listed passes through unchanged. Subqueries, conditional expressions such as CASE WHEN, and time-based functions like SLEEP() can be constructed using characters not present in the blacklist. A whitelist approach — restricting input to known table and column identifiers — would have prevented the injection.

Attack Vector

An attacker authenticated as an administrator sends a crafted HTTP request to /wp-json/imagely/v1/galleries or /wp-json/imagely/v1/albums with a malicious orderby value. The payload is concatenated into the ORDER BY clause, allowing boolean-based, time-based, or UNION-based SQL injection techniques. Attackers can exfiltrate the wp_users table, dump password hashes, read secrets stored in wp_options, or plant administrative accounts.

No verified public exploit code is available. Refer to the Tenable Security Research advisory for technical details.

Detection Methods for CVE-2026-9059

Indicators of Compromise

• HTTP requests to /wp-json/imagely/v1/galleries or /wp-json/imagely/v1/albums containing SQL keywords such as SELECT, UNION, SLEEP, or CASE in the orderby parameter
• Unexpected administrator accounts or modifications to the wp_users and wp_usermeta tables
• Anomalous response latency on NextGEN REST endpoints indicating time-based injection
• Database error messages referencing the ORDER BY clause in PHP or web server logs

Detection Strategies

• Inspect WordPress access logs for REST API calls containing non-alphanumeric characters in the orderby parameter
• Apply Web Application Firewall (WAF) rules that match SQL syntax patterns within imagely/v1 request parameters
• Audit installed NextGEN Gallery versions across managed WordPress sites and flag any prior to 4.2.1

Monitoring Recommendations

• Forward WordPress and web server logs to a centralized analytics platform for correlation against REST endpoint abuse
• Alert on authenticated administrator sessions issuing high volumes of REST API requests to gallery endpoints
• Monitor outbound database query latency and error rates for sustained spikes consistent with blind SQL injection

How to Mitigate CVE-2026-9059

Immediate Actions Required

• Upgrade NextGEN Gallery to version 4.2.1 or later on all WordPress installations
• Rotate WordPress administrator passwords and invalidate active sessions after patching
• Review the wp_users table for unauthorized accounts and audit recent changes to privileged roles
• Restrict administrator capability assignments to the minimum set of trusted operators

Patch Information

The vendor addressed the issue in NextGEN Gallery 4.2.1 by hardening the _clean_column() function. Site operators should update through the WordPress plugin manager or by deploying the updated package directly. See the Tenable Security Research advisory for vendor coordination details.

Workarounds

• Temporarily deactivate the NextGEN Gallery plugin until the patched version is deployed
• Block external access to /wp-json/imagely/v1/galleries and /wp-json/imagely/v1/albums via WAF or web server rules
• Reduce the administrator population and enforce multi-factor authentication on all privileged WordPress accounts

# Block NextGEN REST endpoints at the web server until patched (nginx example)
location ~ ^/wp-json/imagely/v1/(galleries|albums) {
    return 403;
}