CVE-2025-69581: Chamilo LMS Information Disclosure Flaw

CVE-2025-69581 Overview

A sensitive data exposure vulnerability has been discovered in Chamilo LMS version 1.11.2. The Social Network /personal_data endpoint fails to implement proper cache-control headers, allowing sensitive user information to remain accessible in the browser cache even after logout. An attacker with physical access to the same device can use the browser's back button to view confidential personal data belonging to the previously authenticated user.

Critical Impact

Unauthorized disclosure of sensitive personal information enables profiling, impersonation, targeted attacks, and significant privacy violations for Chamilo LMS users.

Affected Products

• Chamilo LMS 1.11.2
• Social Network module (/personal_data endpoint)
• Browser-based sessions on shared or public devices

Discovery Timeline

• 2026-01-16 - CVE CVE-2025-69581 published to NVD
• 2026-01-20 - Last updated in NVD database

Technical Details for CVE-2025-69581

Vulnerability Analysis

This vulnerability is classified under CWE-524 (Use of Cache Containing Sensitive Information). The core issue stems from the Chamilo LMS application's failure to set appropriate HTTP cache-control headers on pages that display sensitive user data. When a user accesses the /personal_data endpoint within the Social Network feature, the page content—including full personal information—is cached by the browser. This cached data persists even after the user logs out of the application, creating a window of opportunity for unauthorized information disclosure.

The attack requires local access to the device where a legitimate user previously authenticated to Chamilo LMS. This makes shared workstations, public computers, and kiosk systems particularly vulnerable to exploitation.

Root Cause

The root cause is the absence of proper HTTP cache-control headers on the /personal_data endpoint. Without headers such as Cache-Control: no-store, no-cache, must-revalidate and Pragma: no-cache, browsers store sensitive page content in their local cache. The application fails to instruct browsers to treat authenticated session data as non-cacheable, leaving sensitive information accessible after session termination.

Attack Vector

The attack vector for this vulnerability is local, requiring physical or remote access to a device where a victim has previously authenticated to Chamilo LMS. The exploitation scenario involves:

1. A legitimate user authenticates to Chamilo LMS and accesses their personal data via the Social Network feature
2. The user logs out of the application, believing their session is terminated
3. An attacker with access to the same browser session uses the back button or accesses browser history
4. The browser displays the cached personal data page without requiring authentication
5. The attacker extracts sensitive personal information for malicious purposes

The vulnerability requires user interaction in that the legitimate user must first access the sensitive endpoint, but no special privileges are required by the attacker—only access to the browser session on the same device.

Detection Methods for CVE-2025-69581

Indicators of Compromise

• Browser cache containing Chamilo LMS /personal_data endpoint responses after user logout
• HTTP response headers from /personal_data endpoint lacking Cache-Control: no-store directives
• Audit logs showing multiple accesses to personal data endpoints from the same browser session
• User reports of unauthorized access to personal information on shared devices

Detection Strategies

• Implement web application firewall (WAF) rules to monitor and alert on missing cache-control headers for authenticated endpoints
• Conduct periodic security audits of HTTP response headers on sensitive application endpoints
• Deploy endpoint detection solutions to monitor for suspicious browser history access patterns
• Review application logs for anomalous access patterns to personal data endpoints

Monitoring Recommendations

• Enable detailed logging for all authenticated endpoint access in Chamilo LMS
• Monitor for access to /personal_data endpoints outside of normal user authentication flows
• Implement session monitoring to detect attempts to access data after logout events
• Configure alerts for HTTP responses containing sensitive data without appropriate cache-control headers

How to Mitigate CVE-2025-69581

Immediate Actions Required

• Upgrade Chamilo LMS to a patched version when available from the vendor
• Implement web server-level cache-control headers as a temporary mitigation
• Educate users about risks of accessing sensitive data on shared or public computers
• Consider disabling the Social Network feature or restricting access to /personal_data endpoint on shared devices

Patch Information

Users should monitor the Chamilo LMS GitHub Repository for official security patches addressing this cache-control vulnerability. Additional technical details and proof-of-concept information are available at the CVE-2025-69581 PoC Repository.

Workarounds

• Configure web server or reverse proxy to inject cache-control headers for authenticated Chamilo LMS endpoints
• Implement browser policies that clear cache on exit for computers accessing Chamilo LMS
• Deploy endpoint management solutions to automatically clear browser data after session termination
• Restrict access to Chamilo LMS from shared or public computers where feasible

# Apache configuration example - add to .htaccess or virtual host
<Location "/main/social/personal_data.php">
    Header set Cache-Control "no-store, no-cache, must-revalidate, max-age=0"
    Header set Pragma "no-cache"
    Header set Expires "0"
</Location>

# Nginx configuration example
location ~ /main/social/personal_data\.php$ {
    add_header Cache-Control "no-store, no-cache, must-revalidate, max-age=0";
    add_header Pragma "no-cache";
    add_header Expires "0";
}