GHSA-wvpp-8hx9-p66j
ADVISORY - githubSummary
Summary
The check_unsafe_options guard can be bypassed on every guarded method (clone/clone_from, fetch/pull/push, ls_remote, iter_commits, blame, archive) by combining a single-character kwarg with split_single_char_options=False. The guard's candidate list omits the smuggled option, but transform_kwarg emits a JOINED -n<value> argv token that git parses as --upload-pack=<cmd>, yielding arbitrary command execution at the default allow_unsafe_options=False. This is an incomplete-fix bypass of commit e8d0fbf7 (the fix for GHSA-r9mr-m37c-5fr3), which only emits value-derived candidates when split_single_char_options is True.
Root Cause
_option_candidates derives value-token candidates only under if len(key)==1 and split_single_char_options: (cmd.py:1048, added by e8d0fbf7). With split_single_char_options=False, _option_candidates([], {"n":"utouch <cmd>;git-upload-pack"}) returns only ['-n'] (not on the denylist), so the guard passes. But transform_kwarg('n', value, split_single_char_options=False) emits the JOINED token -nutouch <cmd>;git-upload-pack (cmd.py:1631). git clusters value-less short flags then parses -u<cmd> = --upload-pack=<cmd> → command execution. The hardened guard WOULD block the joined token if it saw it — the flaw is it never receives it.
Impact
Arbitrary OS command execution as the host process (via --upload-pack) at default allow_unsafe_options=False, affecting all guarded methods that forward kwargs. Precondition: the app forwards a user-controlled kwargs dict containing split_single_char_options=False plus a single-char key (same user-dict-forwarding model GHSA-r9mr-m37c-5fr3 accepts).
Proof of Concept
from git import Repo
Repo.clone_from(src, dst,
n="utouch /tmp/ACE;git-upload-pack",
split_single_char_options=False) # /tmp/ACE created -> ACE
Attack Chain
- Entry: app forwards user kwargs to
Repo.clone_from(url, path, **kwargs):{split_single_char_options: False, n: 'utouch /tmp/ACE;git-upload-pack'}. - Check:
check_unsafe_options(_option_candidates([], kwargs), unsafe_git_clone_options). Guard: denylist includes--upload-pack/-u. Bypass proof:_option_candidatesyields only['-n'](value token skipped becausesplit=False); guard never sees-u. - Sink:
transform_kwargemits joined token (cmd.py:1631). argv (observed):['git','clone','-v','-nutouch /tmp/ACE;git-upload-pack','--','<src>','<dst>']. - Impact: git clusters
-n+-u<cmd>→ runs upload-pack command → ACE.
Bypass Evidence
Independently reproduced (gate harness, default allow_unsafe_options=False): the split=False payload created the marker VH05_GATE_ACE (ACE); the clone returned normally (guard bypassed). Control: n='--upload-pack=…' (split default True) → UnsafeOptionError: --upload-pack is not allowed. Fix-commit read: e8d0fbf7 extends candidates only under if len(key)==1 and split_single_char_options: — split=False skips value emission. Also confirmed the earlier clustering-parse fix (commit 56806080) does not cover this because the guard only ever receives ['-n'].
Affected Versions
GitPython <= 3.1.57 (code present verbatim on the latest release tag).
Suggested Fix
Make _option_candidates emit value-derived candidates regardless of split_single_char_options (i.e. also for the joined -n<value> form), OR run check_unsafe_options over the fully-transformed argv rather than the reconstructed name-only candidate list.
Reported by zx (Jace) — GitHub: @manus-use
Common Weakness Enumeration (CWE)
Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
GitHub
2.8
CVSS SCORE
8.8high| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| gitpython | pypi | - | - | <=3.1.57 | 3.1.58 |
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).
Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.
The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
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.