CVE-2026-33704
Chamilo Lms ≤ 1.11.38
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:LSummary
CVE-2026-33704 is a high-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Chamilo Chamilo Lms. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 35th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-3 (Malicious Code Protection) and CM-7 (Least Functionality) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33704 is an arbitrary file write vulnerability in Chamilo LMS, an open-source learning management system, affecting versions prior to 1.11.38. The issue exists in the BigUpload endpoint, where any authenticated user can specify a filename via the "key" parameter and supply arbitrary content through the raw POST body, which is written directly to the server filesystem. While filenames with .php extensions are sanitized to .phps, the .pht extension passes through unmodified, enabling remote code execution on Apache configurations that interpret .pht files as PHP scripts. The vulnerability is associated with CWE-434 (Unrestricted Upload of File with Dangerous Type) and carries a CVSS v3.1 base score of 7.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L).
Any authenticated user, including low-privilege accounts such as students, can exploit this vulnerability remotely with low attack complexity and no user interaction. By uploading a malicious .pht file containing PHP code, an attacker can achieve remote code execution on the server, potentially leading to full server compromise depending on the environment.
The vulnerability is addressed in Chamilo LMS version 1.11.38. Security practitioners should upgrade to this version immediately. Additional details are available in the GitHub security advisory at https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-phfx-pwwg-945v and the fixing commit at https://github.com/chamilo/chamilo-lms/commit/9748f1ffbdb8b6dc84c0e0591c9d3c1d92e21c00.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21555
Vulnerability Data
Chamilo LMS is a learning management system. Prior to 1.11.38, any authenticated user (including students) can write arbitrary content to files on the server via the BigUpload endpoint. The key parameter controls the filename and the raw POST body becomes…
more
the file content. While .php extensions are filtered to .phps, the .pht extension passes through unmodified. On Apache configurations where .pht is handled as PHP, this leads to Remote Code Execution. This vulnerability is fixed in 1.11.38.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
—
—
—
V5.1.1
Mitigating Controls (NIST 800-53 r5) AI
Malicious-code protection at entry points blocks dangerous file types from being accepted and executed.
Least functionality restricts the file types and automatic processing capabilities the system will accept.
Mobile-code controls define, authorize, and block unacceptable uploaded code before automatic processing occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.
Hardened configuration baselines can enforce allowed file types and processing rules.
Secure development practices include input validation and file-type restrictions that prevent this weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Configuration and acceptance testing verify that file-upload handling enforces allowed types and does not permit dangerous content to be stored or executed.
Secure-coding guidelines and security testing explicitly address restrictions on allowed file types and upload handling, reducing the risk that dangerous file uploads are accepted without validation.
Mandated testing for malicious content and known vulnerabilities reduces the likelihood that an outsourced component will contain or accept dangerous file types that could later be uploaded or executed.
Application allow-listing and pre-use scanning of received files directly blocks the introduction of executable content that has not been vetted, eliminating the primary vector for unrestricted dangerous file uploads.