GitPython before 3.1.54 contains an incomplete denylist for unsafe Git clone options that omits the --template flag, allowing an attacker to supply a directory containing malicious post‑checkout hooks. During a repository clone, the hooks execute, leading to arbitrary command execution on the host. This flaw is a classic example of command injection, as reflected by the associated CWE‑78.

The vulnerability affects all installations of the GitPython library prior to version 3.1.54, as distributed by the GitPython developers. Users must verify the installed version and upgrade if they are running a vulnerable release.

With a CVSS score of 7.7, the exploitation risk is high. The EPSS score is not available, and the vulnerability is not listed in CISA’s KEV catalog, suggesting that broad ecosystem exploitation has not yet been documented. Attackers would need the ability to execute a git clone command with a controllable --template parameter, which could be achieved by hosting a malicious repository or compromising a system that performs cloning from untrusted sources. The potential impact is full remote code execution on the target system.