Session fixation vulnerability in CuppaCMS thru commit 4c9b742b23b924cf4c1f943f48b278e06a17e297 on November 12, 2019 allows attackers to gain access to arbitrary user sessions.
The file manager option in CuppaCMS before 2019-11-12 allows an authenticated attacker to upload a malicious file within an image extension and through a custom request using the rename function provided by the file manager is able to modify the image extension into PHP resulting in remote arbitrary code execution.