CVE-2026-54447

Insecure Permission Assignment for Garmin OAuth Token Store Summary garminconnect (≤ 0.3.4) wrote its OAuth token store to disk without restricting file-system permissions. Under the default Linux umask (022) the token file garmin_tokens.json was created world-readable (0o644). The file contains the DI refresh token, so any other local user on a shared host could read it and obtain persistent, unauthorized access to the victim's Garmin Connect account. - Severity: High - Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource) - Affected versions: <= 0.3.4 - Patched version: 0.3.5 Details Client.dump() created the token directory and file with no mode argument, leaving permissions entirely to the process umask: def dump(self, path: str) -> None: p = Path(path).expanduser() if p.is_dir() or not p.name.endswith(".json"): p = p / "garmin_tokens.json" p.parent.mkdir(parents=True, exist_ok=True) # no mode= p.write_text(self.dumps()) # no permission restriction The serialized payload includes di_token, di_refresh_token, and di_client_id. The call is in the core library (Garmin.login(tokenstore=...) persists tokens this way), and all shipped usage examples default the token store to ~/.garminconnect. Under umask 022 the resulting permissions were: - token directory → 0o755 - garmin_tokens.json → 0o644 (world-readable) A separate, unprivileged user on the same machine could read the file with a plain open() — no elevated privileges required — and extract the refresh token. Impact Local credential theft / privilege escalation on multi-user Linux or macOS hosts running under a permissive umask. The stolen refresh token can be exchanged for fresh access tokens via Garmin's OAuth endpoint, granting ongoing access to the victim's account (health/fitness data, activity history, device management) until the token is revoked. Patch Fixed in 0.3.5 (commit 77a3837). dump() now creates the directory as 0o700 and writes the token file as 0o600 regardless

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