CVE-2025-11556 is an SQL injection vulnerability identified in version 1.0 of the Simple Leave Manager software developed by code-projects. The flaw resides in the /user.php file, where the 'table' parameter is improperly sanitized, allowing an attacker to inject malicious SQL queries. This vulnerability can be exploited remotely without any authentication or user interaction, making it highly accessible to attackers. The injection can lead to unauthorized reading, modification, or deletion of database records, potentially exposing sensitive employee leave data or allowing further compromise of the underlying system. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the vulnerability's network attack vector, low complexity, and no required privileges or user interaction, but limited impact on confidentiality, integrity, and availability. Although no active exploitation has been reported, a public exploit is available, increasing the likelihood of attacks. The vulnerability affects only version 1.0 of Simple Leave Manager, and no official patches or updates have been linked yet, indicating that organizations must implement alternative mitigations or upgrade paths. The lack of authentication requirements and the remote nature of the exploit make this a critical concern for any deployment of this software.

For European organizations using Simple Leave Manager 1.0, this vulnerability could lead to unauthorized access to sensitive HR data, including employee leave records, potentially violating data protection regulations such as GDPR. The SQL injection could allow attackers to extract confidential information, alter records, or disrupt leave management operations, impacting business continuity and employee trust. Given the remote and unauthenticated exploitation vector, attackers could leverage this vulnerability to gain a foothold in corporate networks, potentially escalating privileges or moving laterally. The impact is particularly significant for organizations in regulated sectors (e.g., finance, healthcare, government) where data integrity and confidentiality are paramount. Additionally, exposure of personal data could result in legal penalties and reputational damage. The medium severity rating suggests that while the vulnerability is serious, it may not lead to full system compromise without additional weaknesses. However, the availability of a public exploit increases the urgency for mitigation.

Since no official patches are currently available, European organizations should immediately implement input validation and sanitization controls on the 'table' parameter within /user.php to prevent SQL injection. Employing web application firewalls (WAFs) with custom rules to detect and block SQL injection payloads targeting this parameter can provide interim protection. Restricting database user permissions to the minimum necessary can limit the damage potential if exploitation occurs. Organizations should also monitor logs for suspicious queries or unusual database activity related to the Simple Leave Manager application. If feasible, upgrading to a newer, patched version of the software once available is recommended. Conducting a thorough security review of the application’s codebase for similar injection flaws is advisable. Finally, organizations should ensure backups of critical data are current and tested to enable recovery in case of data corruption or deletion.