CVE-2026-52726

### Summary `dulwich.porcelain.submodule_update`, and by extension `porcelain.clone(..., recurse_submodules=True)`, materializes attacker-controlled submodule paths from a crafted upstream repository without path validation. A malicious `.gitmodules` plus a matching tree gitlink whose `path` is `.git/hooks` (or any other directory inside the parent repository's `.git` directory) causes the attacker's submodule tree contents to be written directly into the victim's `.git/hooks/` directory, preserving executable mode bits. The dropped executables are then run by any subsequent `git` or `dulwich` command that invokes the matching hook, resulting in arbitrary code execution. This is the dulwich equivalent of the upstream Git fixes for CVE-2024-32002 / CVE-2024-32004, which were never propagated into dulwich's separately implemented submodule porcelain. ### Affected - **Package:** `dulwich` (PyPI) - **Affected versions:** `>=0.23.2, <1.2.5` - **Affected platforms:** all (Linux, macOS, Windows). Exploitation does not require a case-insensitive or NTFS filesystem, because the path written is a literal `.git/hooks` rather than a case- or short-name-aliased form. Affected entry points: - `dulwich.porcelain.submodule_update(repo, init=True, recursive=True)` - `dulwich.porcelain.clone(source, target, recurse_submodules=True)` - `dulwich submodule update` CLI / `dulwich clone --recurse-submodules` CLI ### Vulnerable code The submodule path from the tree's gitlink entry (and matching `.gitmodules`) is consumed without validation in [`dulwich/porcelain/submodule.py`](https://github.com/jelmer/dulwich/blob/8efb7d19eac519cd7fac39e79ca354327897e133/dulwich/porcelain/submodule.py#L154-L234). The attacker-controlled `path` enters the loop from `iter_cached_submodules` ([`submodule.py#L154-L168`](https://github.com/jelmer/dulwich/blob/8efb7d19eac519cd7fac39e79ca354327897e133/dulwich/porcelain/submodule.py#L154-L168)): ```python for path, target_sha in submodules_to_update: