GitPython: Unguarded git read-tree option forwarding in IndexFile.from_tree/reset/merge_tree enables arbitrary file overwrite — GitPython
Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')Summary
IndexFile.from_tree, IndexFile.reset (→ from_tree) and IndexFile.merge_tree append caller-influenced treeish strings positionally to git read-tree with no unsafe-option guard, no allow_unsafe_options parameter, and no -- separator. git read-tree --index-output=<file> writes the resulting index to an arbitrary path, and last-occurrence-wins lets an injected --index-output override the method's internal temp path — clobbering an arbitrary file with a valid git-index blob. This is a distinct, never-guarded sink: commit 3af0c251 (GHSA-3f7w-8rr8-f37f) guarded only checkout_index and tag; read_tree was left unprotected (it is among the acknowledged unguarded call sites in that advisory's sweep but was never reported or fixed).
Root Cause
from_tree (index/base.py:388), reset (delegates to from_tree), and merge_tree (index/base.py:291) call repo.git.read_tree(*arg_list) with no check_unsafe_options and no --. The treeish is caller-influenced and positional.
Impact
Arbitrary file overwrite / destruction at the privileges of the host process. Content is constrained to a git-index blob (not attacker-chosen, so not RCE), but the target path is fully attacker-controlled — corrupting/truncating configs or destroying files at attacker-chosen writable locations = I:H + A:H (per the skill's "overwrite-any-path = I:H" rule). Pure VALUE control (positional treeish). Default configuration.
Proof of Concept
IndexFile.from_tree(repo, "--index-output=/home/victim/.bashrc")
# target overwritten with a valid git-index blob (DIRC...)
Attack Chain
- Entry: app calls
IndexFile.from_tree(repo, treeish)/reset(commit=…)/merge_tree(base=…, rhs=…)with attackertreeish="--index-output=/home/victim/.bashrc". - Check: NONE — the methods have no
allow_unsafe_optionsand never callcheck_unsafe_options. - Sink:
repo.git.read_tree(*arg_list)— no--. argv (from_tree, observed):['git','read-tree','--index-output=<tmp>','--index-output=/…/victim'](last-wins). - Impact: target path created/overwritten with a valid git-index blob; existing content destroyed.
Bypass Evidence
Independently reproduced (gate harness): IndexFile.from_tree(repo,'--index-output=<victim>') → victim overwritten; before=IMPORTANT ORIGINAL CONTENT, after starts DIRC\x00\x00\x00\x02… (destructive clobber, valid index blob). reset(commit=…) and both merge_tree positionals verified. Fix-commit read: 3af0c251 touched only checkout_index+tag; read_tree untouched on HEAD.
Affected Versions
GitPython <= 3.1.57 (sinks present verbatim on the latest release tag).
Suggested Fix
Add a check_unsafe_options guard (with an allow_unsafe_options parameter) to from_tree/reset/merge_tree, and/or place a -- separator before the positional treeish arguments; block --index-output (a path-taking option) on this sink.
Reported by zx (Jace) — GitHub: @manus-use
| Software | From | Fixed in |
|---|---|---|
GitPython
|
- | 3.1.58 |
- https://github.com/gitpython-developers/GitPython/commit/9b5dcaf85da5946dbf69dcd53f9edba08f760b32
- https://github.com/gitpython-developers/GitPython/pull/2204
- https://github.com/gitpython-developers/GitPython/releases/tag/3.1.58
- https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-4gmw-gg2m-w46p
Deep Security Visibility Without the Complexity
SynScan provides clear, real-time security insights so you can monitor your attack surface, spot risks early, and act fast—without extra complexity.
- No setup fees
- 5-min deployment
- Cancel anytime
Frequently Asked Questions
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.