Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-4220 is a high-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Chamilo Chamilo Lms. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 0.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
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-2023-4220 is an unrestricted file upload vulnerability in the big file upload functionality located at /main/inc/lib/javascript/bigupload/inc/bigUpload.php within Chamilo LMS versions up to and including 1.11.24. The flaw, tracked under CWE-434 and CWE-79, permits unauthenticated attackers to upload arbitrary files including web shells, enabling stored cross-site scripting and remote code execution on the server.
Attackers with network access can exploit the issue without authentication or user interaction due to missing validation on uploaded content. Successful exploitation grants the ability to execute arbitrary code, achieve full system compromise, and conduct persistent XSS attacks against other users of the learning management platform.
Official advisories and the referenced Chamilo commit 3b487a55076fb06f96809b790a35dcdd42f8ec49 indicate that the vulnerability was addressed through code changes that restrict file uploads. The Chamilo security issues page and the StarLabs advisory both recommend applying the available patch or upgrading to a fixed release to eliminate the unauthenticated RCE and XSS vectors.
The associated EPSS score has remained elevated, with a current value of 0.9249 and a recorded peak of 0.9541.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-54093
Vulnerability Data
Unrestricted file upload in big file upload functionality in `/main/inc/lib/javascript/bigupload/inc/bigUpload.php` in Chamilo LMS <= v1.11.24 allows unauthenticated attackers to perform stored cross-site scripting attacks and obtain remote code execution via uploading of web shell.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.1.1V1.1.2V1.3.2
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.
Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.
Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.
Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.
Validates web inputs to reject script-related content that could produce XSS.
Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.
Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.
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.
Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).
Hardened configuration baselines can enforce allowed file types and processing rules.
Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).
Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.
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.