CVE-2020-37113
Published: 03 February 2026
Description
GUnet OpenEclass 1.7.3 allows authenticated users to bypass file extension restrictions when uploading files. By renaming a PHP file to .php3 or .PhP, an attacker can upload a web shell and execute arbitrary code on the server. This vulnerability enables…
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remote code execution by bypassing the intended file type checks in the exercise submission feature.
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the file extension bypass by requiring validation of uploaded files' types and contents to prevent web shell execution.
Addresses the specific flaw in OpenEclass exercise submission by ensuring timely patching as detailed in the official CHANGES.txt.
Detects and blocks malicious code like renamed PHP web shells during or after upload attempts.
Security SummaryAI
GUnet OpenEclass 1.7.3 contains a file upload vulnerability (CVE-2020-37113, CWE-434) in its exercise submission feature that allows authenticated users to bypass intended file extension restrictions. Attackers can rename a PHP file to extensions like .php3 or .PhP, enabling the upload of a web shell. This flaw leads to remote code execution on the server, with a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Any authenticated user with access to the platform can exploit this vulnerability remotely with low complexity and no user interaction required. Successful exploitation allows the attacker to upload and execute arbitrary code via the web shell, potentially compromising the entire server through full control over confidentiality, integrity, and availability.
Mitigation details are outlined in the official CHANGES.txt file at https://download.openeclass.org/files/docs/1.7/CHANGES.txt. Additional resources include a proof-of-concept exploit at https://www.exploit-db.com/exploits/48163, the OpenEclass website at https://www.openeclass.org/, and a Vulncheck advisory at https://www.vulncheck.com/advisories/gunet-openeclass-e-learning-platform-file-upload-extension-bypass.
A public exploit is available on Exploit-DB, indicating potential for real-world abuse in unpatched e-learning environments.
Details
- CWE(s)
Affected Products
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability is a file upload bypass in a public-facing web application (e-learning platform) that directly enables exploitation of public-facing applications (T1190) and facilitates deployment of a web shell for remote code execution (T1100).