CVE-2025-59540 in LMS
Summary
by MITRE • 03/06/2026
Chamilo is a learning management system. Prior to version 1.11.34, a stored XSS vulnerability exists in Chamilo LMS that allows a staff account to execute arbitrary JavaScript in the browser of higher-privileged admin users. The issue arises because feedback input in the exercise history page is not properly encoded before rendering, allowing malicious scripts to persist in the database and execute on view. This issue has been patched in version 1.11.34.
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Analysis
by VulDB Data Team • 03/06/2026
The vulnerability identified as CVE-2025-59540 represents a critical stored cross-site scripting flaw within the Chamilo learning management system that affects versions prior to 1.11.34. This security weakness specifically targets the exercise history page functionality where user feedback input is processed and stored in the database without adequate sanitization or encoding measures. The vulnerability enables attackers with staff-level access to inject malicious JavaScript code that persists in the system's database and executes when higher-privileged admin users view the affected pages. This creates a dangerous escalation path where lower-privilege users can potentially compromise administrative accounts and gain unauthorized access to sensitive educational data and system controls.
The technical implementation of this vulnerability stems from improper input validation and output encoding practices within the Chamilo LMS codebase. When staff members submit feedback through the exercise history interface, the system fails to properly sanitize the input data before storing it in the database. This lack of proper sanitization means that malicious scripts can be embedded directly into the stored data, which are then rendered unescaped in subsequent page views. The vulnerability specifically affects the rendering process of feedback content on the exercise history page, where the system directly outputs user-provided data without appropriate HTML encoding or script filtering mechanisms. This flaw directly maps to CWE-79, which defines cross-site scripting vulnerabilities as the improper handling of untrusted data in web applications. The vulnerability demonstrates a classic stored XSS pattern where malicious input is stored server-side and then executed client-side when legitimate users access the affected content.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to perform privilege escalation and unauthorized access to administrative functions. When admin users view the exercise history page containing malicious feedback, their browsers execute the injected JavaScript code, potentially allowing attackers to steal session cookies, redirect users to malicious sites, or even execute commands on behalf of the admin users. The vulnerability's exploitation requires only a staff account, making it particularly dangerous as it can be leveraged by insiders or compromised staff members to gain elevated privileges within the learning management system. This represents a significant risk to educational institutions as it could lead to data breaches, unauthorized course modifications, user impersonation, and potential disruption of educational services. The attack vector is particularly concerning because it requires minimal privileges to exploit and can be automated to target multiple administrative users simultaneously.
Mitigation strategies for CVE-2025-59540 should prioritize immediate deployment of the patched version 1.11.34, which implements proper input sanitization and output encoding mechanisms. Organizations should also implement additional defensive measures including regular security audits of user input handling processes, implementation of content security policies to prevent script execution, and monitoring for suspicious activity in the exercise history functionality. The remediation process should include thorough testing to ensure that all user-provided content is properly escaped before storage and rendering, implementing proper input validation routines, and establishing automated scanning processes to detect similar vulnerabilities in other system components. Security teams should also consider implementing web application firewalls and additional monitoring of administrative user sessions to detect potential exploitation attempts. This vulnerability highlights the importance of maintaining current software versions and implementing robust input validation practices as recommended by the ATT&CK framework's defensive techniques for preventing code injection attacks. Organizations should also conduct regular security training for staff members to raise awareness about the potential risks of executing untrusted code and the importance of proper input validation in web applications.