WordPress Contest Gallery Plugin SQL Injection Flaw

The Contest Gallery plugin for WordPress is vulnerable to SQL Injection via the 'form_input' parameter in versions up to, and including, 28.1.6. This is due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query inside the unauthenticated 'post_cg_gallery_form_upload' AJAX action (specifically the 'cb' branch of the included users-upload-check.php, where $f_input_id is concatenated unquoted into 'SELECT Field_Content FROM ... WHERE id = $f_input_id'). The endpoint is gated only by a public frontend nonce ('cg1l_action' / 'cg_nonce') that is exposed in the page source of any public gallery page. This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database.

Casky was already ahead

This CVE exploits attack patterns that Casky's 301matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The Contest Gallery plugin for WordPress contains a critical SQL injection vulnerability in its unauthenticated AJAX handler that processes file upload requests. An attacker can inject arbitrary SQL commands through the 'form_input' parameter without authentication, allowing unauthorized database access, data exfiltration, or manipulation. This affects all installations running version 28.1.6 and earlier of the plugin. The vulnerability stems from insufficient input escaping and the direct concatenation of user-supplied data into SQL queries, creating a high-severity risk for any WordPress site using this gallery functionality.

Casky.ai's 301 mapped skills detect this attack through MITRE ATT&CK techniques TA0001 (Reconnaissance) and TA0043 (Reconnaissance targeting web applications). Practitioners using Casky's Claude-powered analysis would identify suspicious patterns including: anomalous AJAX requests to 'post_cg_gallery_form_upload' with SQL metacharacters in the 'form_input' parameter, unexpected database queries with UNION or SELECT statements in web logs, and database error messages revealing schema information. The extended reasoning capability correlates these indicators with CWE-89 (SQL Injection) patterns, flagging both active exploitation attempts and reconnaissance probing that precedes attack execution. Security teams would see detailed findings linking suspicious form submissions to potential data exfiltration paths within their WordPress environment.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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301 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-8912.

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threat intelligence · low

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threat intelligence · low

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threat intelligence · low

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MITRE ATT&CK Techniques

TA0001 TA0043

Investigate the attack patterns behind CVE-2026-8912

Casky has 301 skills that investigate the attack patterns behind CVE-2026-8912. Run one and get CVSS-scored findings in 3 minutes.

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