CVE-2026-78677: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in gitpython-developers GitPython

GitPython versions prior to 3.1.59 have an improper limitation of pathname to a restricted directory vulnerability (CWE-22, CWE-73) in the Repo.clone_from() and Repo.clone() methods. These methods forward keyword arguments to the underlying git clone command but rely on a denylist (Repo.unsafe_git_clone_options) to block unsafe options. However, this denylist omits the --separate-git-dir option, which allows redirection of the .git metadata directory to an arbitrary path. As a result, an attacker controlling input to separate_git_dir can cause git clone to create repository metadata outside the intended directory, potentially planting malicious files or hooks. This issue is due to a parity gap between denylist entries for git init and git clone commands. The vulnerability has a CVSS 4.0 score of 8.7 (high severity).

An attacker able to supply the separate_git_dir argument to Repo.clone_from() or Repo.clone() can cause GitPython to execute git clone with the --separate-git-dir option pointing to an arbitrary filesystem path. This leads to creation of the full git repository metadata structure, including hooks, at a location outside the intended clone destination. The impact is arbitrary directory and file creation controlled by the attacker, bounded only by the permissions of the process running GitPython. This can facilitate malicious repository manipulation or code execution via planted hooks or files.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid passing the separate_git_dir or separate-git-dir option to Repo.clone_from() or Repo.clone(), or ensure that allow_unsafe_options is not set to True and that input is strictly validated to prevent injection of unsafe options. Monitor vendor advisories for updates addressing the omission of --separate-git-dir from the unsafe_git_clone_options denylist.