CVE-2025-4736 is a SQL Injection vulnerability identified in version 1.1 of the PHPGurukul Daily Expense Tracker application. The vulnerability resides in the /register.php file, specifically in the handling of the 'email' parameter. An attacker can manipulate this parameter to inject malicious SQL code, which the application then executes on its backend database. This type of injection allows an unauthenticated remote attacker to potentially access, modify, or delete sensitive data stored within the database. The vulnerability does not require any user interaction or authentication, making it accessible for exploitation over the network. The CVSS 4.0 base score is 6.9, indicating a medium severity level, with the vector showing network attack vector, low attack complexity, no privileges or user interaction required, and limited impact on confidentiality, integrity, and availability. Although no public exploits are currently known in the wild, the vulnerability has been publicly disclosed, increasing the risk of exploitation by threat actors. The lack of a patch or mitigation guidance from the vendor at this time further elevates the risk for users of this software version. SQL Injection vulnerabilities are critical because they can lead to unauthorized data access, data corruption, or full system compromise depending on the database permissions and application architecture. The Daily Expense Tracker is likely used by individuals or small organizations to manage financial data, which may contain sensitive personal or business information, making the impact of exploitation significant for affected users.

For European organizations using PHPGurukul Daily Expense Tracker 1.1, this vulnerability poses a risk of unauthorized disclosure and manipulation of financial and personal data. Exploitation could lead to data breaches involving sensitive expense records, potentially violating GDPR requirements for data protection and privacy. This could result in regulatory fines, reputational damage, and operational disruption. Since the vulnerability allows remote exploitation without authentication, attackers could automate attacks to compromise multiple installations rapidly. Small and medium enterprises (SMEs) and individual professionals relying on this software for financial tracking are particularly vulnerable due to likely limited cybersecurity resources and delayed patching. Additionally, if the compromised data is used in financial reporting or tax submissions, data integrity issues could have legal and financial consequences. The medium severity rating suggests that while the impact is serious, it may be somewhat limited by the scope of the application and the extent of database privileges accessible via injection. However, the public disclosure increases the urgency for European organizations to assess and mitigate this risk promptly.

1. Immediate mitigation should include disabling or restricting access to the /register.php endpoint until a vendor patch or update is available. 2. Implement Web Application Firewall (WAF) rules specifically targeting SQL Injection patterns on the 'email' parameter to block malicious payloads. 3. Conduct a thorough code review and refactor the input handling in /register.php to use parameterized queries or prepared statements to prevent SQL Injection. 4. Monitor application logs for unusual database query patterns or repeated failed registration attempts that may indicate exploitation attempts. 5. If feasible, migrate to a newer, patched version of the software or consider alternative expense tracking solutions with better security posture. 6. Educate users and administrators on the risks of using outdated software and the importance of timely updates. 7. Perform regular backups of the database to enable recovery in case of data tampering. 8. Review database user permissions to ensure the application has the minimum necessary privileges, limiting the potential damage from injection attacks.