Chamilo LMS, a widely used open-source learning management system, suffers from a critical vulnerability identified as CVE-2026-29041, classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). This vulnerability affects all Chamilo LMS versions prior to 1.11.34. The root cause is the application's insufficient validation of uploaded files: it relies exclusively on MIME-type verification, which can be easily spoofed, and does not validate file extensions or enforce secure server-side storage policies. Consequently, an authenticated user with low privileges can upload a crafted file containing executable code. Once uploaded, the attacker can execute arbitrary commands on the server, leading to remote code execution (RCE). The CVSS v3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability, with network attack vector, low attack complexity, and no user interaction required beyond authentication. The vulnerability was publicly disclosed on March 6, 2026, and patched in version 1.11.34. Although no known exploits have been reported in the wild, the ease of exploitation and potential damage make this a critical risk for organizations using vulnerable versions of Chamilo LMS.

The impact of CVE-2026-29041 is severe for organizations using vulnerable Chamilo LMS versions. Successful exploitation grants attackers remote code execution capabilities, allowing them to execute arbitrary commands on the LMS server. This can lead to full system compromise, data theft, unauthorized access to sensitive educational records, disruption of LMS services, and potential lateral movement within the network. The breach of confidentiality, integrity, and availability can damage organizational reputation, cause regulatory compliance violations, and result in significant operational downtime. Since Chamilo LMS is often deployed in educational institutions and training environments, the compromise could affect large user bases including students, educators, and administrators. The vulnerability’s exploitation does not require user interaction beyond authentication, increasing the risk if low-privileged accounts are compromised or misused.

To mitigate CVE-2026-29041, organizations should immediately upgrade Chamilo LMS to version 1.11.34 or later, where the vulnerability is patched. Beyond upgrading, implement strict server-side validation of uploaded files by enforcing checks on file extensions, content inspection, and restricting upload directories to non-executable locations. Employ application-layer firewalls or web application firewalls (WAFs) to detect and block suspicious upload attempts. Limit file upload permissions to only trusted users and monitor upload activity for anomalies. Additionally, enforce the principle of least privilege on user accounts to reduce the risk posed by compromised low-privileged users. Regularly audit and review LMS configurations and logs for signs of exploitation attempts. Finally, educate administrators and users about secure file handling practices and maintain up-to-date backups to enable recovery in case of compromise.