Medium [CVE-2026-78675] Local file content disclosure via malicious.gitmodules

GitPython before 3.1.59 fails to disable merge_includes when parsing.gitmodules, allowing attackers to disclose local file content by including arbitrary file paths via [include] directives.

Attackers can craft a malicious.gitmodules file with include directives pointing to sensitive files; when repo.submodules is accessed, GitConfigParser raises MissingSectionHeaderError embedding the target file's first line verbatim in the exception message. A flaw was found in GitPython that could allow for local file content disclosure.

This vulnerability occurs because GitPython does not properly disable merge_includes when processing.gitmodules files. An attacker could exploit this by creating a specially crafted.gitmodules file with include directives that reference sensitive local files.

When a user interacts with the repository's submodules, the system may inadvertently reveal the first line of these sensitive files through an error message.

When a user opens an untrusted repository and accesses the repository's submodules (e.g., via repo.submodules), the GitConfigParser may raise a MissingSectionHeaderError that embeds the first line of the target file verbatim in the exception message.

This exception message can be exposed through CI logs, error pages, exception trackers, and code review bots, creating multiple disclosure channels.