Executive Summary

CVE-2026-29861 is a critical SQL Injection vulnerability found in the PHP-MYSQL-User-Login-System version 1.0, specifically in the login.php endpoint.

The vulnerability occurs because the application directly uses unsanitized user inputs in SQL queries without validation or prepared statements.

An attacker can inject SQL code via the username parameter to bypass authentication, for example by using the payload: ' OR '1'='1, which makes the SQL WHERE clause always true and grants unauthorized admin access.

This vulnerability is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command).

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Compliance Impact

The SQL injection vulnerability in PHP-MYSQL-User-Login-System v1.0 allows attackers to bypass authentication and gain unauthorized administrative access, potentially leading to data leakage or manipulation.

Such unauthorized access and potential data compromise can violate common standards and regulations like GDPR and HIPAA, which require protection of personal and sensitive data against unauthorized access and breaches.

Therefore, this vulnerability poses a significant risk to compliance with these regulations by undermining data confidentiality and integrity.

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Impact Analysis

Exploitation of this vulnerability can lead to full authentication bypass, allowing attackers to gain unauthorized administrative access.

Attackers may manipulate or leak sensitive data through SQL injection techniques such as UNION-based queries.

The backend database can be completely compromised, potentially leading to data loss, corruption, or unauthorized data disclosure.

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Detection Guidance

This vulnerability can be detected by attempting to inject SQL payloads into the username parameter at the login.php endpoint and observing if authentication is bypassed.

• Use the payload ' OR '1'='1 in the username field and any value in the password field to test if the login is bypassed.
• Monitor web server logs for suspicious login attempts containing SQL injection patterns such as ' OR '1'='1.
• Use tools like sqlmap to automate detection of SQL injection vulnerabilities against the login.php endpoint.
• Example command with sqlmap: sqlmap -u "http://target/PHP-MYSQL-User-Login-System/login.php" --data="username=' OR '1'='1&password=any" --risk=3 --level=5

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Mitigation Strategies

Immediate mitigation steps include:

• Replace dynamic SQL queries with prepared statements such as mysqli_prepare() or PDO to prevent SQL injection.
• Implement strict input validation and sanitization on all user inputs, especially the username and password fields.
• Deploy a Web Application Firewall (WAF) to block known SQL injection attack patterns.
• Conduct regular code audits and penetration testing to identify and fix similar vulnerabilities.

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