CVE-2026-2503: ElementCamp WordPress Plugin SQLi Flaw

CVE-2026-2503 Overview

The ElementCamp plugin for WordPress contains a time-based SQL Injection vulnerability in the tcg_select2_search_post AJAX action. The vulnerability exists in all versions up to and including 2.3.6, where the meta_query[compare] parameter is improperly handled. User-supplied compare values are placed directly as SQL operators in database queries without validation against an allowlist of permitted comparison operators, enabling authenticated attackers to extract sensitive information from the WordPress database.

Critical Impact

Authenticated attackers with Author-level privileges or higher can exploit this SQL injection vulnerability to extract sensitive data from the database, potentially compromising user credentials, configuration data, and other confidential information stored in WordPress.

Affected Products

• ElementCamp WordPress Plugin versions up to and including 2.3.6
• WordPress installations with vulnerable ElementCamp plugin versions
• Sites where users have Author-level access or above

Discovery Timeline

• 2026-03-21 - CVE CVE-2026-2503 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2026-2503

Vulnerability Analysis

This SQL injection vulnerability (CWE-89) stems from improper input validation in the ElementCamp plugin's Select2 search functionality. The vulnerable code path exists in the tcg-select2.php file, specifically within the tcg_select2_search_post AJAX handler.

The core issue is that while the plugin applies esc_sql() to user input, this sanitization function is ineffective for this particular attack vector. The meta_query[compare] parameter value is used as an SQL operator rather than as a quoted string value within the query. Because the payload operates outside of quotes as an operator, attackers can craft injection payloads that do not contain quote characters, completely bypassing the esc_sql() protection.

Time-based SQL injection techniques allow attackers to infer database contents by measuring response times when conditional sleep statements are executed. This enables data exfiltration character by character, extracting usernames, password hashes, API keys, and other sensitive information stored in the WordPress database.

Root Cause

The root cause is the absence of an allowlist validation for the compare parameter before its use as an SQL operator. The plugin accepts arbitrary user input for the comparison operator position in meta queries, trusting esc_sql() to provide sufficient protection. However, since the value is not wrapped in quotes within the SQL statement, escape sequences have no sanitizing effect on payloads constructed without quote characters. The proper fix requires validating that the compare value matches one of WordPress's permitted meta query operators such as =, !=, >, >=, <, <=, LIKE, NOT LIKE, IN, NOT IN, BETWEEN, NOT BETWEEN, EXISTS, or NOT EXISTS.

Attack Vector

The vulnerability is exploitable over the network by any authenticated user with Author-level privileges or above. The attacker sends a crafted AJAX request to the tcg_select2_search_post action with a malicious meta_query[compare] parameter containing time-based SQL injection payloads.

The attack leverages conditional SQL statements combined with sleep functions to infer database contents. For example, an attacker can determine if a specific character exists at a given position in a database value by observing whether the response is delayed. This technique requires no direct error output or data reflection, making it stealthier but slower than other SQL injection methods.

Exploitation details and vulnerable code references are available in the Wordfence Vulnerability Analysis and the ElementCamp plugin source code.

Detection Methods for CVE-2026-2503

Indicators of Compromise

• Unusual AJAX requests to tcg_select2_search_post with abnormal meta_query[compare] parameter values
• Database query logs showing malformed or extended SQL operators containing SLEEP(), BENCHMARK(), or conditional statements
• Abnormally slow response times for WordPress AJAX endpoints that correlate with specific request patterns
• Web application firewall logs indicating blocked SQL injection attempts targeting ElementCamp plugin endpoints

Detection Strategies

• Deploy web application firewall (WAF) rules to detect SQL injection patterns in WordPress AJAX requests, specifically monitoring the meta_query[compare] parameter
• Enable WordPress database query logging and monitor for anomalous queries containing time-based functions or unexpected operators
• Implement intrusion detection rules to flag requests with SQL injection characteristics targeting the wp-admin/admin-ajax.php endpoint with action=tcg_select2_search_post
• Review web server access logs for repeated POST requests to AJAX endpoints from single IP addresses with varying parameter values

Monitoring Recommendations

• Configure real-time alerting for SQL injection signatures in web traffic destined for WordPress installations
• Monitor user account activity for Author-level and above accounts, watching for unusual AJAX request patterns
• Establish baseline response time metrics for WordPress AJAX endpoints to detect time-based injection attempts through statistical anomaly detection
• Implement database activity monitoring to detect unauthorized SELECT queries against sensitive tables

How to Mitigate CVE-2026-2503

Immediate Actions Required

• Update the ElementCamp plugin to a patched version newer than 2.3.6 immediately
• Temporarily disable the ElementCamp plugin if an update is not yet available
• Review WordPress user accounts and remove or reduce privileges for any accounts with Author-level access that do not require it
• Audit database access logs for signs of prior exploitation and investigate any suspicious query patterns

Patch Information

Organizations should update the ElementCamp WordPress plugin to the latest available version that addresses this vulnerability. Plugin updates can be applied through the WordPress admin dashboard under Plugins > Installed Plugins, or via WP-CLI using wp plugin update element-camp. The patched version should implement proper allowlist validation for the meta_query[compare] parameter.

For technical details on the vulnerable code locations, refer to the tcg-select2.php source code.

Workarounds

• Restrict Author-level and above account access to only trusted users until the plugin is patched
• Implement WAF rules to block requests containing SQL injection patterns in the meta_query[compare] parameter
• Disable AJAX functionality for the ElementCamp plugin by adding a custom WordPress filter or modifying plugin permissions
• Consider temporarily removing the plugin if it is not critical to site operations

# Configuration example: WAF rule to block SQL injection in meta_query compare parameter
# ModSecurity Rule Example
SecRule ARGS:meta_query[compare] "@rx (?i)(\b(sleep|benchmark|if|case|when)\b|--|/\*|\*/)" \
    "id:1001,phase:2,deny,status:403,msg:'SQL Injection attempt in ElementCamp plugin'"