Command execution via short-option token smuggling

Argument injection in GitPython before 3.1.58 allows attackers to execute OS commands via crafted kwargs passed to guarded Git methods. The check_unsafe_options guard examines only the bare single-character option when split_single_char_options=False, but transform_kwarg later joins that key and attacker-controlled value into one token that git reparses as --upload-pack=. Exploitation requires an application to forward attacker-controlled kwargs, including split_single_char_options=False and a single-character key, into methods such as clone_from, fetch, pull, or push; when reachable, code runs with the host process's privileges even though allow_unsafe_options remains false by default.