A server-side injection was possible for a malicious admin to manipulate the application to include a malicious script which is executed by the server. This attack is only possible if the admin uses a client that have been tampered with.
During an internal security assessment, a Server-Side Request Forgery (SSRF) vulnerability that allowed an authenticated attacker to access internal resources on the server was discovered.
The communication protocol used between client and server had a flaw that could lead to an authenticated user performing a remote code execution attack.