CVE-2026-3755: Sales And Inventory System SQLi Flaw

CVE-2026-3755 Overview

A SQL injection vulnerability has been identified in SourceCodester Sales and Inventory System version 1.0. This vulnerability affects the /check_customer_details.php file within the POST Handler component. By manipulating the stock_name1 argument, an attacker can inject malicious SQL queries into the application's database layer. The attack can be executed remotely, and a proof-of-concept exploit has been publicly disclosed.

Critical Impact

Remote attackers with low privileges can exploit this SQL injection vulnerability to compromise database confidentiality, integrity, and availability, potentially leading to unauthorized data access, modification, or deletion.

Affected Products

• SourceCodester Sales and Inventory System 1.0
• ahsanriaz26gmailcom sales_and_inventory_system

Discovery Timeline

• 2026-03-08 - CVE CVE-2026-3755 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2026-3755

Vulnerability Analysis

This SQL injection vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component) exists in the check_customer_details.php file of the Sales and Inventory System. The vulnerability occurs when user-supplied input through the stock_name1 parameter is passed directly to SQL queries without proper sanitization or parameterized query implementation. This allows attackers to inject arbitrary SQL commands that the database server will execute with the application's privileges.

The network-accessible nature of this vulnerability means that any authenticated user with low-level privileges can exploit it remotely. Successful exploitation could allow attackers to read, modify, or delete database records, potentially exposing sensitive customer information, sales records, and inventory data.

Root Cause

The root cause of this vulnerability is improper input validation and the absence of parameterized queries (prepared statements) in the check_customer_details.php file. The application directly concatenates user input from the stock_name1 POST parameter into SQL query strings without sanitizing special characters or using database-specific escaping functions. This fundamental coding flaw allows SQL metacharacters to break out of the intended query context and execute attacker-controlled SQL statements.

Attack Vector

The attack is executed remotely via the network by sending specially crafted HTTP POST requests to the /check_customer_details.php endpoint. An attacker with low-level authentication can manipulate the stock_name1 parameter to inject malicious SQL syntax. The exploitation requires no user interaction, making it highly automatable.

The vulnerability allows injection through the POST handler, where the stock_name1 parameter is processed. Technical details and proof-of-concept information are available in the GitHub PoC Repository.

Detection Methods for CVE-2026-3755

Indicators of Compromise

• Unusual or malformed HTTP POST requests to /check_customer_details.php containing SQL syntax characters such as single quotes, double dashes, or UNION statements
• Database error messages appearing in web server logs or application responses indicating SQL syntax errors
• Unexpected database queries or data modifications in database audit logs
• Abnormal traffic patterns to the Sales and Inventory System web interface

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block SQL injection patterns in POST parameters, particularly targeting the stock_name1 field
• Implement database activity monitoring to alert on suspicious query patterns such as UNION-based injections, time-based blind SQL injection attempts, or unauthorized data extraction
• Enable detailed application and web server logging to capture all requests to check_customer_details.php
• Use intrusion detection systems (IDS) with signatures for common SQL injection attack patterns

Monitoring Recommendations

• Monitor web server access logs for repeated requests to /check_customer_details.php with varying parameter values that contain SQL metacharacters
• Set up alerts for database errors related to SQL syntax in the application's error logs
• Implement rate limiting and anomaly detection for the affected endpoint
• Review database query logs for queries containing injected content or unexpected query structures

How to Mitigate CVE-2026-3755

Immediate Actions Required

• Restrict network access to the Sales and Inventory System to trusted IP addresses only until a patch is applied
• Implement WAF rules to filter malicious input targeting the stock_name1 parameter
• Review and audit database access logs for signs of past exploitation
• Consider temporarily disabling the /check_customer_details.php functionality if it is not business-critical

Patch Information

No official vendor patch has been released at this time. Organizations using SourceCodester Sales and Inventory System 1.0 should monitor SourceCodester for security updates. Additional vulnerability details are available through VulDB #349733.

In the absence of an official patch, organizations with development capabilities should implement parameterized queries (prepared statements) in the check_customer_details.php file to properly handle the stock_name1 parameter input.

Workarounds

• Use prepared statements with parameterized queries if you have access to modify the source code of the application
• Deploy a web application firewall with SQL injection protection rules in front of the application
• Implement input validation at the application layer to reject inputs containing SQL metacharacters
• Restrict database user privileges used by the application to minimum required permissions (principle of least privilege)

# Example: Apache ModSecurity rule to block SQL injection in stock_name1 parameter
SecRule ARGS:stock_name1 "@detectSQLi" \
    "id:100001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'SQL Injection attempt blocked in stock_name1 parameter - CVE-2026-3755'"