CVE-2026-4550: Simple Gym Management System SQLi Flaw

CVE-2026-4550 Overview

A SQL Injection vulnerability has been identified in code-projects Simple Gym Management System up to version 1.0. This security flaw affects the /gym/func.php file, where manipulation of the Trainer_id and fname parameters allows for time-based blind SQL injection attacks. The vulnerability can be exploited remotely without user interaction, enabling attackers with high privileges to potentially extract sensitive data, modify database contents, or disrupt database availability.

Critical Impact

Remote attackers with elevated privileges can exploit this SQL injection vulnerability to compromise database confidentiality, integrity, and availability through the Trainer_id or fname parameters in the /gym/func.php endpoint.

Affected Products

• code-projects Simple Gym Management System version 1.0 and earlier
• PHP-based gym management installations using the vulnerable func.php component

Discovery Timeline

• 2026-03-22 - CVE-2026-4550 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2026-4550

Vulnerability Analysis

This vulnerability is classified as CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component). The flaw exists in the /gym/func.php file where user-supplied input through the Trainer_id and fname parameters is not properly sanitized before being incorporated into SQL queries. This allows attackers to inject malicious SQL statements that are executed by the backend database.

The time-based blind SQL injection technique leverages database sleep functions to infer information about the database structure and contents based on response timing delays. Since the application does not return error messages directly, attackers must rely on timing-based inference to extract data character by character.

Root Cause

The root cause of this vulnerability is the lack of proper input validation and parameterized queries in the /gym/func.php file. User-controlled parameters (Trainer_id and fname) are directly concatenated into SQL query strings without sanitization or the use of prepared statements. This fundamental coding practice violation allows attackers to break out of the intended query context and inject arbitrary SQL commands.

Attack Vector

The attack can be executed remotely over the network. An attacker with high privileges can craft malicious HTTP requests containing SQL injection payloads in the Trainer_id or fname parameters. The time-based blind SQL injection technique works by injecting conditional statements with deliberate time delays (such as SLEEP() or BENCHMARK() functions in MySQL) that cause measurable differences in server response times, allowing data extraction through boolean inference.

For detailed technical analysis and proof-of-concept information, see the GitHub CVE Exploit Report and GitHub CVE Detailed Analysis.

Detection Methods for CVE-2026-4550

Indicators of Compromise

• Unusual HTTP requests to /gym/func.php containing SQL syntax in Trainer_id or fname parameters
• Database query logs showing time-delay functions such as SLEEP(), BENCHMARK(), or WAITFOR DELAY
• Abnormally long response times from the application server correlating with specific request patterns
• Web server access logs containing encoded SQL injection payloads in GET/POST parameters

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block SQL injection patterns in request parameters
• Implement database activity monitoring to identify suspicious queries containing time-delay functions
• Enable detailed application logging for the /gym/func.php endpoint to capture parameter values
• Use intrusion detection systems (IDS) with signatures for time-based SQL injection attack patterns

Monitoring Recommendations

• Monitor web application response times for anomalies that may indicate time-based exploitation attempts
• Review database audit logs for unusual query patterns or unauthorized data access
• Set up alerts for repeated failed authentication attempts combined with SQL injection signatures
• Track network traffic for suspicious patterns targeting the vulnerable endpoint

How to Mitigate CVE-2026-4550

Immediate Actions Required

• Restrict access to the /gym/func.php endpoint through network-level controls or authentication requirements
• Implement input validation to reject special characters and SQL syntax in the Trainer_id and fname parameters
• Deploy a Web Application Firewall (WAF) to filter malicious requests before they reach the application
• Review and audit all database user privileges to enforce least-privilege principles

Patch Information

As of the last CVE update on 2026-03-23, no official vendor patch has been released for this vulnerability. Organizations using code-projects Simple Gym Management System should monitor the Code Projects Resource Hub for security updates. Additional vulnerability details are available at VulDB #352377.

Workarounds

• Implement prepared statements and parameterized queries in the func.php file to prevent SQL injection
• Add server-side input validation to whitelist acceptable characters for Trainer_id (numeric only) and fname (alphanumeric only) parameters
• Deploy a reverse proxy with SQL injection filtering capabilities in front of the application
• Consider temporarily disabling or restricting access to the affected functionality until a proper fix is implemented

The following demonstrates proper parameterized query implementation in PHP:

# Secure query implementation using prepared statements
# Replace direct query concatenation with parameterized queries:
$stmt = $pdo->prepare("SELECT * FROM trainers WHERE trainer_id = ? AND fname = ?");
$stmt->execute([$trainer_id, $fname]);