CVE-2025-4203: wpForo Forum Plugin SQLi Vulnerability

CVE-2025-4203 Overview

The wpForo Forum plugin for WordPress contains a SQL Injection vulnerability in the get_members() function affecting all versions up to and including 2.4.8. The vulnerability exists due to missing integer validation on the offset and row_count parameters. The function blindly interpolates row_count into a LIMIT offset,row_count clause using esc_sql() rather than enforcing numeric values. Since MySQL 5.x's grammar allows a PROCEDURE ANALYSE clause immediately after a LIMIT clause, unauthenticated attackers controlling row_count can append a stored-procedure call, enabling error-based or time-based blind SQL injection that can be used to extract sensitive information from the database.

Critical Impact

Unauthenticated attackers can exploit this SQL Injection vulnerability to extract sensitive information from WordPress databases, potentially compromising user credentials, private content, and site configuration data.

Affected Products

• wpForo Forum plugin for WordPress versions up to and including 2.4.8
• WordPress sites using vulnerable wpForo Forum installations
• MySQL 5.x database backends supporting PROCEDURE ANALYSE syntax

Discovery Timeline

• 2025-10-25 - CVE-2025-4203 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-4203

Vulnerability Analysis

This SQL Injection vulnerability (CWE-89) stems from inadequate input validation in the get_members() function within the wpForo Forum plugin. The function constructs SQL queries using the offset and row_count parameters without proper type enforcement. While the code uses esc_sql() for sanitization, this function is designed for escaping string values and does not enforce numeric types for integer parameters.

The vulnerability allows unauthenticated remote attackers to manipulate the LIMIT clause in database queries. By injecting specially crafted payloads into the row_count parameter, attackers can append MySQL-specific syntax such as PROCEDURE ANALYSE() to perform error-based or time-based blind SQL injection attacks. This technique leverages MySQL 5.x's parser behavior that permits the PROCEDURE ANALYSE clause immediately following a LIMIT clause.

Root Cause

The root cause is improper input validation in the get_members() function located in classes/Members.php. The code fails to enforce integer type casting on the offset and row_count parameters before incorporating them into the SQL LIMIT clause. Using esc_sql() alone is insufficient because this function escapes strings for SQL contexts but does not validate or convert values to integers. The correct approach would be to use intval() or absint() to ensure these parameters contain only numeric values before query construction.

Attack Vector

The attack can be executed over the network without authentication. An attacker can craft malicious HTTP requests targeting WordPress endpoints that invoke the get_members() function with manipulated row_count parameter values. By appending SQL syntax after the expected numeric value, the attacker can:

1. Inject PROCEDURE ANALYSE() calls to trigger MySQL errors that reveal database information
2. Implement time-based blind SQL injection using SLEEP() or BENCHMARK() functions to exfiltrate data character by character
3. Extract sensitive information including user credentials, email addresses, and private forum content

The vulnerability is particularly dangerous because it requires no user interaction and can be exploited by completely unauthenticated remote attackers. For detailed technical analysis, refer to the Wordfence Vulnerability Report and the vulnerable code in Members.php.

Detection Methods for CVE-2025-4203

Indicators of Compromise

• Unusual database error messages in web server logs containing SQL syntax errors or PROCEDURE ANALYSE references
• HTTP request parameters containing SQL keywords such as PROCEDURE, ANALYSE, SLEEP, or BENCHMARK in pagination-related fields
• Abnormal database query execution times indicating time-based blind SQL injection attempts
• Unexpected outbound network connections from the database server

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect SQL injection patterns in HTTP request parameters targeting wpForo endpoints
• Monitor WordPress database query logs for anomalous LIMIT clauses containing non-numeric characters or PROCEDURE ANALYSE syntax
• Deploy intrusion detection signatures to identify SQL injection payloads in HTTP traffic to /wp-content/plugins/wpforo/ paths
• Enable verbose logging on MySQL servers to capture unusual query patterns and slow query alerts

Monitoring Recommendations

• Configure real-time alerting for database errors containing SQL syntax violations or injection indicators
• Implement rate limiting on WordPress member listing endpoints to detect automated exploitation attempts
• Review WordPress access logs regularly for requests with abnormal parameter lengths or encoded SQL keywords
• Monitor database connection patterns for unusual query volumes or timing anomalies

How to Mitigate CVE-2025-4203

Immediate Actions Required

• Update wpForo Forum plugin to version 2.4.9 or later immediately
• Audit WordPress database for signs of data exfiltration or unauthorized access
• Review web server and database logs for exploitation attempts
• Temporarily disable the wpForo Forum plugin if immediate patching is not possible

Patch Information

The wpForo development team has addressed this vulnerability in version 2.4.9. The fix implements proper integer validation on the offset and row_count parameters before SQL query construction. Administrators should update through the WordPress admin dashboard or download the latest version from the wpForo plugin page. The patched code can be reviewed in the updated Members.php file.

Workarounds

• Deploy a Web Application Firewall with SQL injection protection rules to filter malicious requests targeting wpForo endpoints
• Implement server-level input validation using ModSecurity or similar modules to block requests containing SQL injection patterns
• Restrict database user privileges for the WordPress application to limit potential damage from successful exploitation
• Consider temporarily disabling public access to member listing functionality until the patch can be applied

# Configuration example for ModSecurity WAF rule
# Add to modsecurity.conf or custom rules file
SecRule ARGS "@rx (?i)(PROCEDURE\s+ANALYSE|SLEEP\s*\(|BENCHMARK\s*\()" \
    "id:100001,phase:2,deny,status:403,msg:'SQL Injection attempt blocked - CVE-2025-4203'"