CVE-2026-78675

GitPython (version 3.1.58 and earlier; flaw confirmed at repo HEAD commit 9729ed3b dated 2026-08-05) exposes local file contents because Submodule._config_parser(), which parses every repository's .gitmodules file, constructs SubmoduleConfigParser without disabling the merge_includes default of True, so [include] directives embedded in .gitmodules are followed and merged. An attacker who controls the .gitmodules of a repository that a victim clones can point an include at any readable local file — absolute paths short-circuit any path join, relative paths are joined with no check that they stay inside the repository, and '~' is expanded — with the only pre-open gate being a readability check. When the targeted file lacks a git-config [section] header, which is true of most non-config files, the raised MissingSectionHeaderError embeds the verbatim first line of the file in its message, and files that do parse are merged into the submodule configuration, either disclosing or incorporating local file content. Any application, CI job, or automation that enumerates or reads submodule configuration (repo.submodules, Submodule.config(), Submodule.iter_items()) on repositories from untrusted sources is affected. There is no known public proof-of-concept, the flaw is not in CISA KEV, and EPSS puts 30-day exploitation probability at about 0.1 percent, so no exploitation is currently known.

What to do: Upgrade to the first GitPython release after 3.1.58 that addresses this issue once published (no fixed version in the source data), and confirm the fix passes merge_includes=False when Submodule._config_parser() builds its parser. Until then, avoid calling repo.submodules, Submodule.config(), or Submodule.iter_items() on repositories cloned from untrusted sources, or first inspect their .gitmodules for [include] directives referencing absolute, relative-with-traversal, or home-directory paths. Review logs for MissingSectionHeaderError messages, since these may have already leaked the first line of sensitive local files.