GHSA-956x-8gvw-wg5v

## Summary GitPython spawns the real `git` binary with an argument vector built from caller-supplied values. To prevent argument injection, GitPython maintains denylists of "unsafe" Git options (`--upload-pack`, `--receive-pack`, `--exec`, `-c`, `--config`, …) that can be abused to run arbitrary commands, and enforces them with `Git.check_unsafe_options()`. That enforcement is only wired into the **network** commands — `clone_from`, `Remote.fetch`, `Remote.pull`, `Remote.push`. Several other public APIs that also forward caller-controlled values into the `git` argv have **no guard at all**: 1. **`Repo.archive(ostream, treeish=None, prefix=None, **kwargs)`** forwards `**kwargs` verbatim into `git archive`. An attacker-influenced options mapping such as `{"remote": ".", "exec": "<cmd>"}` becomes `git archive --remote=. --exec=<cmd> -- <treeish>`, and `git archive --remote=<local repo>` invokes `git-upload-archive` whose path is overridden by `--exec` → **arbitrary command execution under default Git configuration** (no `protocol.ext.allow` needed). 2. **`repo.git.ls_remote(<url>, upload_pack="<cmd>")`** (and the dynamic-command builder generally) turns the `upload_pack` kwarg into `--upload-pack=<cmd>` with no guard → **arbitrary command execution**. 3. **`Repo.iter_commits(rev)`** and **`Repo.blame(rev, file)`** place the caller's `rev` value into the argv *before* the `--` end-of-options separator and apply no leading-dash check. A benign-looking ref value such as `--output=/path/to/file` is parsed by `git rev-list` / `git blame` as the `--output` option, which **opens and truncates an arbitrary file** before Git even validates the revision → arbitrary file clobber (integrity/availability; can destroy keys, configs, lockfiles, or be aimed at files the host later sources). The first two are direct code execution; the third is an arbitrary file-overwrite primitive. All share one root cause: the `check_unsafe_options` / end-of-options discipline that GitPython ap