Newbie question .. can some one please help me understand the attack scenario. if I, as the attacker, want to inject malicious code/binary into a git repo, then

Newbie question .. can some one please help me understand the attack scenario. if I, as the attacker, want to inject malicious code/binary into a git repo, then I need to write my malicious code/binary in such a way that the resultant hash collides with one of the commits (? Or the last one?) in the repo. Is this correct?