CVE-2020-22755: 
Java vulnerability analysis and mitigation

File upload vulnerability in MCMS 5.0 allows attackers to execute arbitrary code via a crafted thumbnail. The vulnerability was discovered in the article management functionality where attackers can bypass file upload restrictions and perform directory traversal attacks. This vulnerability is tracked as CVE-2020-22755 and is distinct from CVE-2022-31943 (NVD).

The vulnerability exists in the article management feature where users can upload thumbnail images. The system implements file extension restrictions to prevent uploading of executable files like .exe and .jsp, but these can be bypassed by adding a trailing dot to the filename (e.g., 'malicious.jsp.'). Additionally, the code lacks proper validation for directory traversal characters (../), allowing attackers to upload files to arbitrary directories. The vulnerability has been assigned a CVSS v3.1 base score of 8.8 (HIGH) with the vector string: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD).

Successful exploitation of this vulnerability allows attackers to execute arbitrary code on the target system by uploading malicious files to arbitrary locations on the server. This can lead to complete system compromise, including unauthorized access to sensitive data, system modification, and potential remote code execution (NVD).

The vulnerability affects MCMS version 5.0. Users should implement proper input validation for file uploads, including strict filename validation and prevention of directory traversal attempts. Additionally, implementing proper access controls and file upload restrictions is recommended (NVD).