Affected: gitpython-developers GitPython

GitPython before 3.1.52 is vulnerable to environment-variable exfiltration in Repo.clone_from(). The caller-supplied remote URL is passed through Git.polish_url(), which on non-Cygwin platforms calls os.path.expandvars() on the URL before invoking git clone. An attacker who controls the clone URL can embed $NAME or ${NAME} tokens that are expanded to the values of the hosting process's environment variables (e.g., AWS_SECRET_ACCESS_KEY or GITHUB_TOKEN). The resulting URL, now containing the secret, is transmitted over the network to an attacker-controlled host during the clone attempt, disclosing the secret.

Affected: PyPI: GitPython

### Summary `Repo.clone_from()` passes the caller-supplied remote URL through `Git.polish_url()`, which on every non-Cygwin platform calls `os.path.expandvars()` on the URL before handing it to `git clone`. An attacker who controls the URL argument — the documented use case for `clone_from()` in "import repository from URL" features of CI servers, git-hosting mirrors, and dependency scanners — can embed `$NAME` / `${NAME}` tokens that are expanded server-side to the values of the hosting process's environment variables. The resulting URL, now containing the secret, is transmitted over the network to the attacker-named host. This crosses the trust boundary between an untrusted remote URL and the server's process environment, disclosing secrets such as `AWS_SECRET_ACCESS_KEY` or `GITHUB_TOKEN` with no precondition beyond the ability to submit a clone URL.

### Details **Affected versions:** `gitpython` (PyPI) — all releases up to and including `3.1.50` (latest at time of reporting); confirmed present on the `main` branch.

`Git.polish_url()` unconditionally applies environment-variable expansion to its input on the non-Cygwin branch:

`git/cmd.py` (v3.1.50), lines 907–925: ```python @classmethod def polish_url(cls, url: str, is_cygwin: Union[None, bool] = None) -> PathLike: """Remove any backslashes from URLs to be written in config files. ... """ if is_cygwin is None: is_cygwin = cls.is_cygwin()

if is_cygwin: url = cygpath(url) else:…

Affected: PyPI: gitpython

### Summary `Repo.clone_from()` passes the caller-supplied remote URL through `Git.polish_url()`, which on every non-Cygwin platform calls `os.path.expandvars()` on the URL before handing it to `git clone`. An attacker who controls the URL argument — the documented use case for `clone_from()` in "import repository from URL" features of CI servers, git-hosting mirrors, and dependency scanners — can embed `$NAME` / `${NAME}` tokens that are expanded server-side to the values of the hosting process's environment variables. The resulting URL, now containing the secret, is transmitted over the network to the attacker-named host. This crosses the trust boundary between an untrusted remote URL and the server's process environment, disclosing secrets such as `AWS_SECRET_ACCESS_KEY` or `GITHUB_TOKEN` with no precondition beyond the ability to submit a clone URL.

### Details **Affected versions:** `gitpython` (PyPI) — all releases up to and including `3.1.50` (latest at time of reporting); confirmed present on the `main` branch.

`Git.polish_url()` unconditionally applies environment-variable expansion to its input on the non-Cygwin branch:

`git/cmd.py` (v3.1.50), lines 907–925: ```python @classmethod def polish_url(cls, url: str, is_cygwin: Union[None, bool] = None) -> PathLike: """Remove any backslashes from URLs to be written in config files. ... """ if is_cygwin is None: is_cygwin = cls.is_cygwin()

if is_cygwin: url = cygpath(url) else:…