GitPython is a python library used to interact with Git repositories. Prior to 3.2.1, create_submodule() in git/objects/submodule/base.py accepts an attacker-influenced submodule path such as .git/hooks and invokes _clone_repo() before safely rejecting the destination. In 3.1.x, _validate_repo_path() does not exist and the call succeeds silently, while in 3.2.0 and later affected revisions the check in git/index/base.py raises ValueError only after the clone has written to disk and does not remove the planted file. An attacker-controlled submodule can therefore place an executable post-checkout hook that a later Git operation executes. Exploitation requires an application to accept an untrusted submodule path and a clone destination such as .git/hooks that is empty enough for Git to clone into it, which commonly means that default sample hooks are absent. This issue is fixed in version 3.2.1.
https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-83vg-56qc-22m7
https://github.com/gitpython-developers/GitPython/releases/tag/3.2.1
https://github.com/gitpython-developers/GitPython/pull/2264
https://github.com/gitpython-developers/GitPython/commit/97eadb888d2f99567e3113f4e455be4ca128f697