Remote Command Execution in gogs/gogs

A remote command execution vulnerability exists in gogs/gogs versions <=0.12.7 when deployed on a Windows server. The vulnerability arises due to improper validation of the `tree_path` parameter during file uploads. An attacker can set `tree_path=.git.` to upload a file into the .git directory, allowing them to write or rewrite the `.git/config` file. If the `core.sshCommand` is set, this can lead to remote command execution.