CVE-2025-65670 is an Insecure Direct Object Reference (IDOR) vulnerability identified in classroomio version 0.1.13, a platform used for educational course management. The vulnerability arises because the application fails to properly enforce access control on certain admin and teacher endpoints. Specifically, authenticated students can manipulate course ID parameters in URLs to gain temporary unauthorized access to sensitive information related to courses, administrative functions, and student data. This exposure is transient, as the system reverts to normal access restrictions shortly after the unauthorized access attempt. The vulnerability requires the attacker to be authenticated as a student but does not require any additional user interaction beyond modifying URL parameters. The CVSS 3.1 base score of 4.3 reflects that the attack vector is network-based, with low attack complexity, requiring privileges but no user interaction, and impacts confidentiality only to a limited extent without affecting integrity or availability. No patches or known exploits are currently available, indicating that the vulnerability is newly disclosed and not yet actively exploited. The underlying cause is a failure to validate user authorization for requested resources, a classic example of CWE-639 (Authorization Bypass Through User-Controlled Key).

For European organizations, particularly educational institutions using classroomio or similar platforms, this vulnerability poses a risk of unauthorized disclosure of sensitive educational data, including course materials, administrative details, and student information. Although the exposure is momentary and the confidentiality impact is limited, such data leaks can undermine trust, violate data protection regulations such as GDPR, and potentially expose personally identifiable information (PII). The vulnerability does not impact system integrity or availability, so operational disruption is unlikely. However, the ability for students to access admin-level data could facilitate further social engineering or targeted attacks. Institutions with large deployments of classroomio or those integrating it with other systems may face increased risk. The lack of known exploits reduces immediate threat but does not eliminate the risk of future exploitation once details become widely known.

To mitigate CVE-2025-65670, organizations should implement strict server-side access control checks that verify the requesting user's role and permissions against the requested resource identifiers. This includes validating that students cannot access admin or teacher endpoints by manipulating URL parameters. Employ parameterized access control logic rather than relying on client-side controls or obscurity. Conduct thorough code reviews and penetration testing focusing on IDOR vulnerabilities. Monitor web server logs and application telemetry for unusual access patterns, such as students accessing admin URLs or multiple rapid course ID changes. If possible, apply virtual patching via web application firewalls (WAFs) to block suspicious requests targeting admin endpoints by non-admin users. Educate developers on secure coding practices related to authorization and implement automated security testing in the CI/CD pipeline. Finally, coordinate with the classroomio vendor for official patches and updates once available.