External risk intelligence

Chamilo LMS Arbitrary File Upload Leading to Code Execution.

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2023-34944

Chamilo is a Learning Management System typically deployed as a public-facing web application. The vulnerability exists in a file upload component, which is a standard functional part of a web-accessible LMS used by students and instructors over the internet.

Unrestricted File Upload

Chamilo Lms

1.11.0 to 1.11.18

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability affects the Chamilo learning management system, specifically its file upload functionality. It allows for the execution of arbitrary code by uploading a malicious file, posing a significant risk to systems and data. The main concern is confirming relevance and exposure.

Unrestricted file uploads can allow code execution.
Critical vulnerability in a widely used LMS.
Confirm relevance and assess exposure.

Attack Path

How an attacker could exploit the issue

An attacker can exploit this vulnerability by sending a specially crafted SVG file to the web server. The vulnerability lies within the file upload functionality, which is exposed to the network and does not require authentication. If successful, this could allow an attacker to execute arbitrary code on the server.

No authentication required for access.
Uploading a malicious SVG file.
Arbitrary code execution on the server.

Live Threat

Current exploitation, exposure, and threat context

An arbitrary file upload vulnerability in the file upload component could allow an unauthenticated attacker to execute arbitrary code on the server by uploading a crafted SVG file. This could affect the confidentiality, integrity, and availability of the Chamilo Learning Management System.

Server-side code execution.
Uploading malicious SVG files.
Compromised system and data.

Operational Fix

Recommended remediation, mitigation, and detection steps

Given the nature of Chamilo LMS often being internet-facing, the platform or application owner is likely responsible for addressing this critical vulnerability. The immediate first step is to locate all instances of the affected Chamilo LMS, confirm their accessibility and business criticality, and identify the specific team or individual accountable for each deployment before planning any remediation.

Identify affected Chamilo LMS instances.
Verify reachability and business criticality.
Plan remediation with the accountable owner.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is Chamilo LMS?

Chamilo LMS is an open-source learning management system designed to support educators and students in creating and managing online courses. It provides various collaborative tools for e-learning, including file sharing and assignment submission modules. Because these modules often require users to upload documents, they interact directly with server-side components that process and store user-provided files.

What does CVE-2023-34944 mean?

This CVE refers to a vulnerability classified as CWE-434, which is Unrestricted Upload of File with Dangerous Type. In this specific case, the software fails to properly validate the contents of uploaded files. An attacker can use this weakness to upload a specially crafted SVG file that the server misinterprets, ultimately allowing the attacker to run unauthorized commands or code on the underlying system.

How is this vulnerability triggered?

An attacker triggers this flaw by interacting with the file upload functionality in the affected component. Because the system does not sufficiently inspect the uploaded file, the attacker can submit a malicious SVG file without needing any prior user account or special permissions. Simply uploading a legitimate image or a standard non-malicious file does not trigger the vulnerability; it requires a specifically crafted file designed to exploit the processing logic.

Why should I care about this Chamilo LMS bug?

If your instance is reachable over the internet, it is at higher risk because attackers can reach the vulnerable component without network restrictions. According to Halo Surface Signal, Chamilo is typically deployed as a public-facing application, meaning it is often directly accessible to unauthorized users. If your installation is internet-facing, it provides a clear path for remote attackers to attempt code execution.

What should I do if I use Chamilo?

Your first step is to perform an inventory of all Chamilo LMS deployments within your environment to determine which versions are active. Once identified, confirm the accessibility of each instance and verify if it is exposed to the public internet. After assessing the business criticality of those specific installations, coordinate with the system owners to prioritize the necessary security updates to address the file upload weakness.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.