CVE-2026-78678: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') in gitpython-developers GitPython

The vulnerability arises because the denylist of unsafe git revision options in GitPython's Repo.blame() and Repo.blame_incremental() methods only includes '--output' and '-o', which are write-related options. However, git blame also supports '--contents <file>' and '-S <file>', which cause the blame output to include lines from an arbitrary file. These options are not on the denylist, so a user-controlled revision string containing '--contents=<path>' passes the safety check and is executed, leaking file contents. The flaw is due to the denylist approach focusing only on write options rather than all options that take filesystem paths. This affects GitPython versions up to 3.1.58.

An attacker who can control the revision argument to Repo.blame() or Repo.blame_incremental() can cause the application to read arbitrary local files and include their contents in the blame output. This results in an arbitrary local file read vulnerability at the privileges of the process running GitPython. No privilege escalation or code execution is indicated.

No official patch or fix is explicitly stated in the provided data. The suggested fix is to replace the denylist with an allowlist of safe blame options or at minimum add '--contents' and '-S' to the denylist of unsafe options. Until a fix is released, users should avoid passing untrusted input to the revision parameter of Repo.blame() and Repo.blame_incremental(). Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.