GitPython's IndexFile.remove() and Head.checkout() methods forward **kwargs directly into git rm and git checkout commands without guarding unsafe options. By passing --pathspec-from-file=<file> together with --pathspec-file-nul, Git treats the entire file as a single NUL-delimited pathspec. When the pathspec does not match any files, Git outputs an error message quoting the entire file contents verbatim. GitPython surfaces this error output through GitCommandError.stderr, effectively leaking the contents of any file accessible to the caller. This vulnerability affects GitPython versions prior to 3.1.58 and is a variant of a previously assessed issue (GHSA-3f7w-8rr8-f37f) but at different call sites that were previously considered safe. The root cause is the lack of validation or restriction on unsafe git command options in these methods.

An attacker with the ability to invoke these GitPython methods with crafted parameters can read arbitrary files on the system that the process has access to. This can lead to disclosure of sensitive information such as configuration files or credentials. The vulnerability does not allow code execution or modification, only information disclosure. The CVSS score of 6.5 reflects a medium severity impact with network attack vector, low attack complexity, and requiring some privileges.

A patch is available in GitPython version 3.1.58 that addresses this issue by properly guarding unsafe options in the affected methods. Users should upgrade to version 3.1.58 or later to remediate this vulnerability. Until patched, avoid passing untrusted input to the pathspec_from_file and pathspec_file_nul parameters in IndexFile.remove() and Head.checkout().