CVE-2025-65681 identifies a security vulnerability in Overhang.IO's tutor-open-edx platform version 20.0.2, an open-source solution widely used for deploying Open edX instances. The vulnerability stems from the absence of proper cache-control HTTP headers combined with insufficient client-side session checks. Cache-control headers are critical for instructing browsers and intermediary caches on how to handle sensitive content; their absence can cause sensitive pages or data to be cached improperly, potentially exposing them to unauthorized users with local access to the system or device. Additionally, relying solely on client-side session validation is insecure because attackers with local access can bypass these checks to access restricted information. This vulnerability requires local unauthorized access, meaning an attacker must already have some level of access to the host or device running the platform. There are no known public exploits or patches available at the time of publication, which increases the urgency for organizations to implement mitigations proactively. The vulnerability primarily threatens confidentiality by enabling unauthorized disclosure of sensitive educational or user data. The lack of server-side session enforcement and cache-control headers represents a design weakness that could be exploited in environments where multiple users share devices or where local attackers have physical or logical access. Given the platform's use in educational institutions and corporate training environments, the exposure of sensitive user data could lead to privacy violations and compliance issues.

For European organizations, especially educational institutions and corporate training providers using tutor-open-edx, this vulnerability poses a risk of sensitive data leakage. Unauthorized local users could access cached pages or bypass session checks to retrieve confidential information such as user credentials, course materials, or personal data. This could lead to privacy breaches, reputational damage, and potential non-compliance with GDPR and other data protection regulations. The impact is heightened in shared device environments like computer labs or training centers common in Europe. Although remote exploitation is not possible, insider threats or compromised local accounts could leverage this vulnerability. The absence of proper cache-control headers also increases the risk of data exposure via browser history or intermediary caches. This could undermine trust in e-learning platforms and disrupt educational operations. Furthermore, organizations may face legal and regulatory consequences if sensitive personal data is exposed due to inadequate session management and caching policies.

European organizations should immediately review and update their tutor-open-edx deployments to implement strict cache-control HTTP headers such as 'Cache-Control: no-store, no-cache, must-revalidate' and 'Pragma: no-cache' on all sensitive pages and API responses. Server-side session validation must be enforced to ensure that session checks cannot be bypassed by manipulating client-side controls. Access to the platform should be restricted to trusted users with proper authentication and authorization mechanisms, minimizing the risk of local unauthorized access. Regular audits of session management and caching configurations should be conducted to detect and remediate misconfigurations. Organizations should also educate users about the risks of shared devices and encourage secure logout practices. Where possible, multi-factor authentication and endpoint security controls should be deployed to reduce insider threat risks. Monitoring for unusual local access patterns and implementing endpoint detection and response (EDR) solutions can help identify exploitation attempts. Finally, organizations should track updates from Overhang.IO for official patches and apply them promptly once available.