CVE-2026-3753: Sales And Inventory System SQLi Vulnerability

CVE-2026-3753 Overview

A SQL Injection vulnerability has been identified in SourceCodester Sales and Inventory System up to version 1.0. The vulnerability exists in an unknown function within the /add_sales_print.php file, where improper handling of the sid parameter allows attackers to inject malicious SQL queries. This vulnerability can be exploited remotely, and proof-of-concept exploit code has been publicly disclosed.

Critical Impact

Remote attackers can exploit this SQL Injection vulnerability to manipulate database queries, potentially leading to unauthorized data access, data modification, or complete database compromise.

Affected Products

• SourceCodester Sales and Inventory System version 1.0
• ahsanriaz26gmailcom sales_and_inventory_system

Discovery Timeline

• 2026-03-08 - CVE CVE-2026-3753 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2026-3753

Vulnerability Analysis

This SQL Injection vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component) occurs in the /add_sales_print.php file of the Sales and Inventory System. The sid parameter is not properly sanitized before being incorporated into SQL queries, allowing attackers to inject arbitrary SQL commands.

The vulnerability is remotely exploitable, meaning attackers do not require local access to the target system. Authentication is required to exploit this vulnerability, but once authenticated, an attacker can manipulate the sid parameter to execute arbitrary SQL statements against the backend database.

Root Cause

The root cause of this vulnerability is improper input validation and the lack of parameterized queries (prepared statements) when handling user-supplied input in the sid parameter. The application directly concatenates user input into SQL queries without proper sanitization or escaping, enabling injection attacks.

Attack Vector

The attack can be conducted remotely over the network. An authenticated attacker can craft malicious HTTP requests to the /add_sales_print.php endpoint with specially crafted sid parameter values containing SQL injection payloads. These payloads can be designed to:

• Extract sensitive data from the database
• Modify or delete existing records
• Bypass authentication mechanisms
• Potentially execute system commands depending on database configuration

The vulnerability is exploited by manipulating the sid parameter in requests to /add_sales_print.php. The attacker injects SQL syntax that alters the intended query logic. For detailed technical information and proof-of-concept examples, refer to the GitHub PoC Repository.

Detection Methods for CVE-2026-3753

Indicators of Compromise

• Unusual or malformed requests to /add_sales_print.php containing SQL syntax characters such as single quotes ('), double dashes (--), or semicolons (;) in the sid parameter
• Database error messages in application logs indicating SQL syntax errors
• Unexpected database queries or data extraction patterns in database audit logs
• Anomalous data access patterns or bulk data retrieval from the application

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block SQL injection patterns in HTTP requests targeting /add_sales_print.php
• Monitor application and database logs for SQL error messages or unusual query patterns
• Deploy intrusion detection systems (IDS) with SQL injection signature rules
• Enable database query logging and monitor for suspicious SELECT, UNION, or data exfiltration queries

Monitoring Recommendations

• Configure real-time alerting for requests containing common SQL injection payloads targeting the sid parameter
• Implement database activity monitoring to detect unauthorized data access or modification
• Review web server access logs for repeated requests to /add_sales_print.php with varying parameter values
• Set up anomaly detection for unusual traffic patterns to the vulnerable endpoint

How to Mitigate CVE-2026-3753

Immediate Actions Required

• Restrict access to the /add_sales_print.php endpoint to only trusted users and IP addresses
• Implement input validation to reject sid parameter values containing non-numeric characters or SQL syntax
• Deploy a Web Application Firewall (WAF) with SQL injection protection rules
• Consider temporarily disabling the affected functionality until a patch is available

Patch Information

No official vendor patch information is currently available for this vulnerability. Users should monitor SourceCodester for security updates. For additional vulnerability details, refer to VulDB #349731.

Workarounds

• Implement parameterized queries (prepared statements) in the application code to prevent SQL injection
• Apply strict input validation to ensure the sid parameter contains only expected numeric values
• Deploy a reverse proxy or WAF with SQL injection filtering capabilities in front of the application
• Limit database user privileges to reduce the impact of successful exploitation

# Example WAF rule to block SQL injection attempts (ModSecurity)
SecRule ARGS:sid "@detectSQLi" \
    "id:100001,\
    phase:2,\
    deny,\
    status:403,\
    msg:'SQL Injection attempt detected in sid parameter',\
    logdata:'Matched Data: %{MATCHED_VAR} found within %{MATCHED_VAR_NAME}'"