CVE-2026-73623 in GitPython
Summary
by MITRE • 08/13/2026
GitPython before 3.1.54 contains an incomplete denylist in unsafe_git_clone_options that omits --template, allowing attackers to achieve arbitrary command execution during clone operations. Attackers can supply --template pointing to a directory containing malicious post-checkout hooks that execute when git clones the repository.
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Analysis
by VulDB Data Team • 08/13/2026
The vulnerability in GitPython versions prior to 3.1.54 represents a critical security flaw that stems from an incomplete denylist implementation within the unsafe_git_clone_options function. This weakness creates a pathway for remote code execution during git clone operations by failing to properly block the --template option, which is a legitimate git command parameter that can be exploited for malicious purposes. The issue manifests when attackers craft clone operations that include the --template flag pointing to directories containing specially crafted post-checkout hooks designed to execute arbitrary commands on the target system.
The technical implementation of this vulnerability leverages the fundamental behavior of git's clone functionality where the --template option specifies a directory containing template files that are copied into the new repository. When combined with malicious hook scripts placed within the template directory, particularly in the hooks/post-checkout file, attackers can achieve arbitrary code execution on systems performing git clone operations. This attack vector operates through the principle of command injection via configuration parameters, where legitimate git options are repurposed to execute unauthorized code.
The operational impact of this vulnerability extends beyond simple code execution to encompass potential system compromise and lateral movement within network environments. Attackers can leverage this flaw to deploy backdoors, exfiltrate data, or establish persistent access points when systems perform automated git clone operations, which are common in CI/CD pipelines, deployment scripts, and development workflows. The vulnerability is particularly dangerous because it operates at the level of git's core functionality rather than application-level code, making it difficult to detect through traditional application security measures.
Security professionals should note this issue aligns with CWE-78 and CWE-94 categories, representing command injection vulnerabilities that allow arbitrary code execution through improper input validation. The ATT&CK framework categorizes this as a technique involving execution through a compromised system, specifically under T1059.006 for command and scripting interpreter and potentially T1203 for exploitation of remote services. Organizations should implement immediate mitigation strategies including updating to GitPython 3.1.54 or later, reviewing all git clone operations for potential exposure, and implementing network-level restrictions on git operations that could be exploited.
The root cause analysis reveals a fundamental flaw in the security model where the denylist approach proves insufficient against evolving attack vectors, particularly when dealing with legitimate git options that can be repurposed. This vulnerability demonstrates the importance of comprehensive input validation rather than relying solely on incomplete blacklists, as well as the need for security teams to understand how legitimate software features can be exploited when not properly secured at the parameter level. The fix implemented in GitPython 3.1.54 addresses this by properly including --template in the denylist, preventing its use in unsafe clone operations while maintaining functionality for legitimate use cases.
Organizations using GitPython should conduct comprehensive security assessments to identify systems that may be vulnerable to this attack vector, particularly those with automated deployment processes or CI/CD environments where git clone operations are performed without proper validation. The vulnerability also highlights the importance of input sanitization and the principle of least privilege when executing system commands through software interfaces. Security teams should monitor for potential exploitation attempts in their logs, looking for unusual git clone patterns that might indicate malicious use of the --template option.
The broader implications extend to software supply chain security, where compromised repositories can be used to distribute malicious code through legitimate git operations. This vulnerability underscores the need for robust security practices in development tooling and emphasizes that even well-established libraries can contain critical security flaws that require ongoing vigilance and maintenance. The incident serves as a reminder of the critical importance of keeping development tools updated and implementing proper security controls in automated systems where git operations are performed without user intervention or explicit validation of parameters.
Mitigation strategies should include immediate patching of GitPython installations, implementation of runtime monitoring for suspicious git clone activities, and consideration of additional security layers such as containerization or sandboxed environments for execution of git operations. Organizations should also review their development workflows to ensure that automated systems performing git operations are properly secured against parameter injection attacks and that all git-related operations undergo appropriate input validation before execution.