CVE-2026-78676: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') in gitpython-developers GitPython

GitPython's GitConfigParser reads multi-line config values using standard git syntax, decoding escape sequences into embedded newlines. However, when rewriting the config file, GitPython uses an unsafe serialization method that replaces embedded newlines with a newline plus tab without proper quoting or continuation markers. This causes the second line of a multi-line value to be interpreted as a new config directive on subsequent reads. An attacker can craft a dormant multi-line config value that, after a legitimate config write operation by GitPython, injects a new core.hooksPath directive pointing to attacker-controlled hooks. Since Git hooks are executed by many git operations, this leads to arbitrary code execution. The vulnerability exists because the injection guard only applies to write-time arguments, not to values read from disk and rewritten. The affected version is GitPython 3.1.58 and earlier, fixed in 3.1.59.

An attacker who can place a specially crafted multi-line config value in a Git repository's config file or an included config file can cause GitPython to rewrite the config file in a way that injects a new core.hooksPath directive. This directive controls the path for Git hooks, which are executed by many Git commands. As a result, arbitrary code execution can occur when the host application or user performs any hook-triggering Git operation. The vulnerability is critical due to the potential for remote code execution without authentication or user interaction.

A fix is available in GitPython version 3.1.59 that addresses this issue by correcting the unsafe re-serialization of multi-line config values. Users should upgrade to GitPython 3.1.59 or later. Until upgraded, avoid performing config write operations on repositories with untrusted or attacker-controlled multi-line config values. Review and sanitize any included config files to ensure they do not contain malicious multi-line values. No other mitigations are documented by the vendor.