The vulnerability identified as CVE-2025-69581 affects Chamillo LMS version 1.11.2, specifically its Social Network /personal_data endpoint. The core issue is the absence of proper cache-control headers on this endpoint, which causes sensitive user information to remain cached in the browser even after the user logs out. When a user logs out, the session is terminated, but the browser cache still holds the personal data. Using the browser's back button restores this cached data, allowing anyone with access to the same device to view full personal information without re-authentication. This exposure can lead to serious privacy violations including user profiling, impersonation, and targeted attacks against the affected users. The vulnerability does not require an attacker to be authenticated or to perform complex actions; it exploits standard browser behavior related to caching. Although no known exploits are currently reported in the wild, the risk is significant due to the ease of access to sensitive data. The lack of patch links suggests that a fix may not yet be available, emphasizing the need for immediate mitigation steps. This vulnerability primarily impacts confidentiality and privacy, with no direct effect on system integrity or availability. The issue is particularly critical in environments where devices are shared or publicly accessible, such as educational institutions or corporate training centers using Chamillo LMS.

For European organizations, this vulnerability poses a substantial risk to user privacy and data protection compliance, especially under GDPR regulations which mandate strict controls over personal data exposure. Educational institutions, corporate training providers, and any organizations using Chamillo LMS risk unauthorized disclosure of sensitive user information if devices are shared or not properly secured. The exposure can lead to profiling and impersonation attacks, potentially resulting in reputational damage, legal penalties, and loss of user trust. In sectors with high sensitivity around personal data, such as healthcare training or government-related education programs, the impact could be more severe. Additionally, the ease of exploitation means that even low-skilled attackers or unauthorized users with physical access to a device can retrieve confidential information. This vulnerability could also facilitate targeted phishing or social engineering attacks by exposing detailed user profiles. Overall, the threat undermines the confidentiality pillar of information security and could have cascading effects on organizational security posture and compliance obligations.

Organizations should immediately implement HTTP cache-control headers such as 'Cache-Control: no-store, no-cache, must-revalidate' and 'Pragma: no-cache' on all sensitive endpoints, especially /personal_data, to prevent browsers from caching sensitive information after logout. Chamillo LMS administrators should monitor for updates or patches from the vendor addressing this vulnerability and apply them promptly once available. In the interim, organizations should enforce strict logout procedures and educate users to close browser windows or clear cache after sessions, particularly on shared devices. Deploying endpoint security controls that restrict unauthorized physical access to devices can reduce risk. Additionally, configuring session timeouts and multi-factor authentication can help mitigate risks from session hijacking or impersonation attempts. Regular security audits and penetration testing focused on session management and caching behavior are recommended to identify similar issues. Finally, organizations should review their data protection policies to ensure compliance with GDPR and other relevant regulations, documenting mitigation efforts and user awareness campaigns.