Affected: gitpython-developers GitPython

GitPython before 3.1.59 fails to safely re-serialize multi-line git-config values during write operations, corrupting dormant quoted values into injected directives like core.hooksPath. Attackers can craft config files with embedded newlines that become live git directives after any unrelated GitPython config write, enabling arbitrary code execution via hook invocation.

Affected: PyPI: GitPython

- **CWE:** CWE-88 (Argument Injection) / CWE-94 (Code Injection) — via a read-then-corrupt-on-rewrite config round trip, not a direct setter argument - **Affected component:** `git/config.py` — `GitConfigParser._read()` (multi-line value decoding, lines 444-541, esp. `string_decode()` at line 460 and its call sites at 519/541) and `GitConfigParser._write()`/`write_section()` (serialization, lines ~694-712, esp. line 708) - **Affected version:** GitPython at HEAD (`9729ed3b948f2bde09f1f188c5311e172212b67e`, 2026-08-05, VERSION `3.1.58`)

## Reachability GitPython added `UNSAFE_CONFIG_CHARS_RE` / `_value_to_string_safe()` / `_assure_config_name_safe()` guards (commits `c417af46`, `1ed1b924`, `a495ccd3`, and PR #2176) to reject a Python string containing a raw `\r`/`\n`/NUL byte, or syntax-bearing characters, when it is passed as an **argument** to `set()`, `set_value()`, `add_value()`, or `add_section()`. This closed the four config-injection GHSAs above.

That guard is applied only on the write-argument surface. It is never consulted for values that entered `GitConfigParser._sections` via `_read()` — i.e. values that came from parsing an on-disk config file. And `_read()` legitimately supports standard, spec-compliant git config syntax for multi-line values: a quoted value that is not closed on the same physical line continues onto the next physical line (git's own backslash-continuation syntax), and `string_decode()` (`.decode('unicode_escape')`) decodes a literal two-charac…

Affected: PyPI: gitpython

GitPython before 3.1.59 fails to safely re-serialize multi-line git-config values during write operations, corrupting dormant quoted values into injected directives like core.hooksPath. Attackers can craft config files with embedded newlines that become live git directives after any unrelated GitPython config write, enabling arbitrary code execution via hook invocation.