VulnerabilityPublished 27 Oct 2026

GitPython: arbitrary file read via attacker-controlled branch name in `Head.checkout()` (incomplete fix of

Affects GitPythonSource GCVE Database

Mentioned vulnerabilities

CVSS 7.1 High : upgrade to 3.2.0 soon.

Data as of 27 Oct 2026, 17:27 UTC

CVSS 4.0 base score

7.1High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 3.2.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

What to do

Upgrade GitPython to 3.2.0.

Affected software

Product	Affected	Fixed in
PyPIGitPython	Affected <3.2.0	Fixed in 3.2.0

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AI-suggested

Upgrade GitPython to version 3.2.0 or later, where this vulnerability is fixed. The fix properly sanitizes the positional branch name argument in Head.checkout(). Until upgrading, avoid cloning and checking out untrusted repositories using vulnerable GitPython versions. No other mitigations are documented by the vendor.

Description

GitPython versions up to 3.1.62 contain a vulnerability in the Head.checkout() method that allows an attacker to cause an arbitrary file read via a specially crafted branch name. The flaw arises because the positional branch name argument is not properly sanitized and is passed directly to the git checkout command without a separator, enabling injection of options such as --pathspec-from-file to read files like /etc/passwd. This issue is an incomplete fix of previous advisories and affects all published releases up to 3.1.62. A fix is available in version 3.2.0.

Impact

An unauthenticated attacker who can supply a repository URL to an application using GitPython can cause that application to clone a malicious repository with a crafted default branch name. This leads to arbitrary file read on the host running the application, exposing sensitive information such as system files. The attacker requires no credentials or privileges in the consuming application. The vulnerability affects any environment that clones untrusted repositories and checks out the default branch using the vulnerable GitPython versions.

Summary

The vulnerability in GitPython's Head.checkout() method occurs because it only guards keyword arguments against unsafe Git options but does not inspect the positional branch name argument. An attacker controlling a repository with a default branch named as a malicious Git option (e.g., --pathspec-from-file=/etc/passwd) can cause the application cloning that repository and checking out the default branch to read arbitrary files accessible to the process. This is a variant of previously fixed issues (CVE-2026-76217 and CVE-2026-78679) where positional argument checks were incomplete. The affected versions include all releases up to 3.1.62, and the vulnerability has a CVSS 3.1 score of 7.5 (High). The issue was fixed in GitPython 3.2.0.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #20OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
ICMP Echo Request Ping (opens in a new tab)
TCP SYN Scan (opens in a new tab)
Enumerate Mail Exchange (MX) Records (opens in a new tab)
DNS Zone Transfers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-73External Control of File Name or Path (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product allows user input to control or influence paths or file names that are used in filesystem operations.
Architecture and Design
When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt".
Architecture and Design · Operation
Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.2 (opens in a new tab)
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
Leverage Alternate Encoding (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
URL Encoding (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-88Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') (opens in a new tab)
Base weaknessOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.
Implementation · Parameterization
Where possible, avoid building a single string that contains the command and its arguments. Some languages or frameworks have functions that support specifying independent arguments, e.g. as an array, which is used to automatically perform the appropriate quoting or escaping while building the command.
Architecture and Design · Input Validation
Understand all the potential areas where untrusted inputs can enter your product: parameters or arguments, cookies, anything read from the network, environment variables, request headers as well as content, URL components, e-mail, files, databases, and any external systems that provide data to the application.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
Attack patterns
Flash Parameter Injection (opens in a new tab)
Using Meta-characters in E-mail Headers to Inject Malicious Payloads (opens in a new tab)
HTTP Parameter Pollution (HPP) (opens in a new tab)
OS Command Injection (opens in a new tab)
Parameter Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Oct 2026, 17:27 UTC

WeaknessesCWE-200, CWE-73, CWE-88

Technical details

References

Community reviews

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