The vulnerability identified as CVE-2025-69581 affects Chamillo LMS version 1.11.2, specifically the Social Network /personal_data endpoint. The issue stems from the absence of proper cache-control headers, which causes sensitive user data to be stored in the browser cache even after the user logs out. Consequently, when a user presses the browser's back button, the cached page is restored, revealing full personal information to anyone with access to the device. This flaw violates secure session termination principles and exposes confidential data such as personal identifiers, potentially including names, contact details, or other sensitive profile information. The vulnerability is classified under CWE-524 (Information Exposure Through Cache). Exploitation requires local access to the device and user interaction (pressing the back button), but no authentication or elevated privileges are necessary. The CVSS 3.1 score is 5.5 (medium severity), reflecting the local attack vector, low complexity, no privileges required, but requiring user interaction. The impact is primarily on confidentiality, with no direct effect on integrity or availability. No patches or known exploits are currently available, so mitigation relies on configuration changes and user awareness. This vulnerability can lead to profiling, impersonation, and targeted attacks if an unauthorized person gains access to the device after logout.

For European organizations using Chamillo LMS, this vulnerability poses a significant privacy risk, especially in environments where devices are shared or not physically secured, such as educational institutions, training centers, or corporate learning environments. Unauthorized access to cached personal data can lead to identity theft, profiling, and social engineering attacks targeting employees or students. The exposure of sensitive information may also violate GDPR requirements regarding data protection and secure session management, potentially resulting in regulatory penalties and reputational damage. While the vulnerability does not allow remote exploitation, the risk is heightened in scenarios where devices are shared or left unattended. The inability to fully clear sensitive data after logout undermines user trust and may impact compliance with European data privacy laws.

To mitigate CVE-2025-69581, organizations should implement the following specific actions: 1) Configure Chamillo LMS or the underlying web server to include strict cache-control headers (e.g., 'Cache-Control: no-store, no-cache, must-revalidate') on all sensitive endpoints, especially /personal_data, to prevent caching of personal information. 2) Ensure that logout functionality properly invalidates sessions and triggers cache clearing mechanisms on the client side. 3) Educate users to close browser tabs or clear browsing data after logout, particularly on shared devices. 4) Where possible, enforce device-level security policies such as screen locking and session timeouts to reduce unauthorized local access. 5) Monitor for updates or patches from Chamillo LMS developers and apply them promptly once available. 6) Conduct regular security reviews and penetration tests focusing on session management and cache control. 7) Consider deploying Content Security Policy (CSP) headers to limit exposure of sensitive data in the browser environment. These measures go beyond generic advice by focusing on cache-control header configuration and user behavior in shared device contexts.