CVE-2025-48373 is a medium-severity vulnerability affecting versions of the open-source school management system software Schule prior to 1.0.1. The core issue is an incorrect authorization mechanism (CWE-863) stemming from reliance on client-side JavaScript to enforce role-based access control. Specifically, the application uses a client-side variable, data.role, to determine user roles and redirect users to appropriate panels. Because this value is controlled on the client side, an attacker can manipulate it via browser developer tools or by intercepting and modifying API responses. By setting data.role to arbitrary values such as "admin," an attacker can bypass server-side authorization checks and gain unauthorized access to restricted administrative areas. This vulnerability does not require authentication or user interaction and can be exploited remotely over the network. The CVSS 4.0 score is 6.6 (medium), reflecting the network attack vector, low attack complexity, no privileges or user interaction required, but with high impact on integrity due to unauthorized access to privileged functions. No known exploits are currently reported in the wild. The root cause is the failure to enforce server-side authorization controls and the insecure trust in client-side data for critical security decisions. This flaw allows privilege escalation and unauthorized access, potentially exposing sensitive student and administrative data or enabling malicious administrative actions within the school management system.

For European organizations, especially educational institutions using Schule, this vulnerability poses significant risks. Unauthorized access to administrative panels can lead to exposure or manipulation of sensitive student records, grades, attendance, and personal information, violating GDPR and other data protection regulations. Attackers could alter administrative settings, disrupt school operations, or create backdoors for persistent access. The impact extends beyond confidentiality to integrity and availability of critical school management functions. Given the widespread adoption of open-source solutions in European public education sectors, exploitation could affect multiple schools or districts, leading to reputational damage, regulatory penalties, and operational disruptions. The lack of authentication or user interaction required for exploitation increases the risk of automated or opportunistic attacks. Although no exploits are known yet, the vulnerability’s simplicity and severity warrant urgent attention.

Immediate mitigation requires upgrading Schule to version 1.0.1 or later, where server-side authorization is properly enforced. Until patching is possible, organizations should implement compensating controls such as: 1) Deploying Web Application Firewalls (WAFs) with rules to detect and block anomalous requests attempting to escalate roles or access admin endpoints. 2) Conducting thorough server-side validation of user roles and permissions independent of client-side data. 3) Implementing strict API security measures including authentication tokens and role verification on the server. 4) Monitoring logs for unusual access patterns or repeated attempts to manipulate roles. 5) Educating administrators and users about the risks of client-side manipulation and enforcing secure development practices. Additionally, network segmentation to isolate school management systems and limiting access to trusted IP ranges can reduce exposure. Regular security audits and penetration testing focused on authorization controls are recommended to prevent similar issues.