{"id":"GHSA-w8jc-g24h-crhw","summary":"GitPython command wrappers omit unsafe protocol and option checks","details":"### Summary\n\nGitPython has spent 2022-2026 rolling out two reusable guards method-by-method: `Git.check_unsafe_protocols(url)` (raises `UnsafeProtocolError` for `\u003ctransport\u003e::` remote-helper URLs - CVE-2022-24439) and `Git.check_unsafe_options(...)` (raises `UnsafeOptionError` for denylisted option spellings - CVE-2023-40267, CVE-2026-42215, CVE-2026-67323). Three wrapper methods that build a `git` argv from caller-controlled values still have **neither**:\n\n1. **`Git.ls_remote`** (git/cmd.py:1128-1143) - checks options (:1139-1141) but forwards the URL positional unchecked; no `allow_unsafe_protocols` parameter exists. The same URL through `clone_from` raises `UnsafeProtocolError`.\n2. **`Repo.merge_base`** (git/repo/base.py:895-936) - forwards `**kwargs`/`*rev` to `self.git.merge_base` with no guard; guarded sibling `iter_commits` sits 12 lines up. Its exception handler additionally swallows every non-128 `GitCommandError` into `[]`, masking the injection.\n3. **`IndexFile.move`** (git/index/base.py:1092-1168) - forwards `**kwargs` to `git mv` twice (:1147, :1167); guarded sibling `remove()` is 23 lines above.\n\nVerified unfixed on `main @ a54d159` (2026-09-21), post-dating latest release 3.1.62 (2026-09-07) - all three sites re-verified today.\n\n### Impact\n\n**Site 1 (`ls_remote`)** - RCE conditional on the victim git transport policy. The common 'probe first, then clone' pattern (`Git(...).ls_remote(attacker_url)`) with an `ext::sh -c ...` URL executes arbitrary commands when the victim git permits the ext transport: dynamically verified with `protocol.ext.allow=always` (marker executed). git \u003e= 2.38.1 stock config refuses the transport (`fatal: transport 'ext' not allowed`, rc 128) - GitPython adds no defense-in-depth and surfaces a bare `GitCommandError`. Environments on git \u003c 2.38.1 are exposed with stock config - the exact population CVE-2022-24439 was scored against.\n\n**Sites 2/3** - latent argument-injection surface: caller kwargs flow 1:1 into the `git` argv before operands and `--` (cmd.py:1850 `opt_args + ext_args`), and `execute_kwargs` (incl. `shell=True`/`env` - the CVE-2023-40267 Windows mechanism) passes through unguarded. Today `git merge-base`/`git mv` expose no exec option, so we claim the missing-guard class (vendor-settled by CVE-2026-67323, which bundled archive/ls_remote/iter_commits/blame in one advisory), not direct RCE.\n\n### Dynamic verification (today; GitPython main @ a54d159, git 2.55.0, Linux)\n\n| # | Call | Result |\n|---|---|---|\n| T1 | `repo.git.ls_remote('ext::/tmp/gp_touch.sh')`, stock config | git refuses (rc 128); **no `UnsafeProtocolError` from GitPython** |\n| T1b | same + victim config `protocol.ext.allow=always` | **marker created - arbitrary command executed** |\n| T2 | `repo.git.ls_remote('.', upload_pack=...)` | blocked by cmd.py:1141 (options-side fixed - protocol-side is the residual gap) |\n| T3 | `repo.merge_base('main','side', upload_pack=...)` | **not blocked**; argv `git merge-base --upload-pack=... main side`; rc 129 silently converted to `[]` |\n| T4 | `repo.index.move(['f1','f2'], output=...)` | **not blocked**; option reaches `git mv` (rc 129) |\n\n### Coverage matrix (main @ a54d159)\n\n`check_unsafe_protocols`: 7 call sites (`_clone`, `archive`, `set_url`, `create`, `fetch`, `pull`, `push`) - none on `ls_remote`.\n`check_unsafe_options`: 24 call sites incl. `ls_remote`, `iter_commits`, `IndexFile.remove` - absent on `merge_base` and `move`.\n\n### Precedents (same repo, same guard family)\n\n- **CVE-2022-24439 / GHSA-hcpj-qp55-gfph** (critical): `check_unsafe_protocols` on the clone path - Site 1 is the same `ext::` primitive on a sibling API.\n- **CVE-2023-40267 / GHSA-pr76-5cm5-w9cj** (critical, 'incomplete fix for CVE-2022-24439'): `check_unsafe_options` - unguarded kwargs to argv treated as RCE (`shell=True` on Windows).\n- **CVE-2026-42215 / GHSA-rpm5-65cw-6hj4** (high, fixed 3.1.47): underscored-spelling bypass - rollout still active in 2026.\n- **CVE-2026-67323 / GHSA-956x-8gvw-wg5v** (high, 8.4, fixed 3.1.51): added `check_unsafe_options` to `archive`/`ls_remote`/`iter_commits`/`blame`; its PoC is literally `repo.git.ls_remote('.', upload_pack=...)`. Establishes that a wrapper missing the check is itself a vulnerability. This report is the residual gap of that rollout: `ls_remote` got options but not protocols; `merge_base`/`move` got neither.\n\n### Recommended fix (existing helpers, 1-3 lines per site)\n\n1. `Git.ls_remote`: `if not allow_unsafe_protocols: self.check_unsafe_protocols(args[0])` + new `allow_unsafe_protocols: bool = False` (the `_clone` pattern, base.py:1536-1538).\n2. `Repo.merge_base`: `check_unsafe_options(Git._option_candidates(list(rev), kwargs), unsafe_options=self.unsafe_git_revision_options)` (the `iter_commits` pattern); stop masking non-128 statuses.\n3. `IndexFile.move`: the `remove()` pattern with `unsafe_git_pathspec_from_file_options`.\n\nOne advisory, three affected methods, severity anchored on Site 1 - mirroring CVE-2026-67323's bundling.","aliases":["CVE-2026-110857"],"modified":"2026-10-27T15:47:24.947223105Z","published":"2026-10-27T15:26:43Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-10-27T15:26:43Z","nvd_published_at":null,"cwe_ids":["CWE-1287"]},"references":[{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-w8jc-g24h-crhw"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/pull/2251"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/commit/9ad28cc4c7176d22cd6181d69805058a719dd03b"},{"type":"PACKAGE","url":"https://github.com/gitpython-developers/GitPython"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/releases/tag/3.2.0"}],"affected":[{"package":{"name":"gitpython","ecosystem":"PyPI","purl":"pkg:pypi/gitpython"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.2.0"}]}],"versions":["0.1.7","0.2.0-beta1","0.3.0-beta1","0.3.0-beta2","0.3.1-beta2","0.3.2","0.3.2.1","0.3.2.RC1","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","1.0.0","1.0.1","1.0.2","2.0.0","2.0.1","2.0.2","2.0.3","2.0.4","2.0.5","2.0.6","2.0.7","2.0.8","2.0.9","2.0.9.dev0","2.0.9.dev1","2.1.0","2.1.1","2.1.10","2.1.11","2.1.12","2.1.13","2.1.14","2.1.15","2.1.2","2.1.3","2.1.4","2.1.5","2.1.6","2.1.7","2.1.8","2.1.9","3.0.0","3.0.1","3.0.2","3.0.3","3.0.4","3.0.5","3.0.6","3.0.7","3.0.8","3.0.9","3.1.0","3.1.1","3.1.10","3.1.11","3.1.12","3.1.13","3.1.14","3.1.15","3.1.16","3.1.17","3.1.18","3.1.19","3.1.2","3.1.20","3.1.22","3.1.23","3.1.24","3.1.25","3.1.26","3.1.27","3.1.28","3.1.29","3.1.3","3.1.30","3.1.31","3.1.32","3.1.33","3.1.34","3.1.35","3.1.36","3.1.37","3.1.38","3.1.4","3.1.40","3.1.41","3.1.42","3.1.43","3.1.44","3.1.45","3.1.46","3.1.47","3.1.48","3.1.49","3.1.5","3.1.50","3.1.51","3.1.52","3.1.53","3.1.54","3.1.55","3.1.56","3.1.57","3.1.58","3.1.59","3.1.6","3.1.60","3.1.61","3.1.62","3.1.7","3.1.8","3.1.9"],"database_specific":{"last_known_affected_version_range":"\u003c= 3.1.62","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-w8jc-g24h-crhw/GHSA-w8jc-g24h-crhw.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}