{"id":"CVE-2026-54447","aliases":["PYSEC-2026-3467"],"url":"https://o3.security/vulnerability/CVE-2026-54447","summary":"garminconnect Has Insecure Permission Assignment for Garmin OAuth Token Store","details":"## Insecure Permission Assignment for Garmin OAuth Token Store\n\n### Summary\n\n`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.\n\n- **Severity:** High\n- **Weakness:** CWE-732 (Incorrect Permission Assignment for Critical Resource)\n- **Affected versions:** `<= 0.3.4`\n- **Patched version:** `0.3.5`\n\n### Details\n\n`Client.dump()` created the token directory and file with no `mode` argument, leaving permissions entirely to the process umask:\n\n```python\ndef dump(self, path: str) -> None:\n    p = Path(path).expanduser()\n    if p.is_dir() or not p.name.endswith(\".json\"):\n        p = p / \"garmin_tokens.json\"\n    p.parent.mkdir(parents=True, exist_ok=True)   # no mode=\n    p.write_text(self.dumps())                     # no permission restriction\n```\n\nThe 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`.\n\nUnder `umask 022` the resulting permissions were:\n\n- token directory → `0o755`\n- `garmin_tokens.json` → `0o644` (world-readable)\n\nA separate, unprivileged user on the same machine could read the file with a plain `open()` — no elevated privileges required — and extract the refresh token.\n\n### Impact\n\nLocal 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.\n\n### Patch\n\nFixed in **0.3.5** (commit `77a3837`). `dump()` now creates the directory as `0o700` and writes the token file as `0o600` regardless of umask — using `os.open(..., O_CREAT|O_WRONLY|O_TRUNC, 0o600)` with `O_NOFOLLOW` where available, plus a defensive `chmod` that also tightens a pre-existing loose file:\n\n```python\np.parent.mkdir(mode=0o700, parents=True, exist_ok=True)\nwith contextlib.suppress(OSError):\n    p.parent.chmod(0o700)\nflags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC\nif hasattr(os, \"O_NOFOLLOW\"):\n    flags |= os.O_NOFOLLOW\nfd = os.open(p, flags, 0o600)\nwith os.fdopen(fd, \"w\", encoding=\"utf-8\") as f:\n    f.write(self.dumps())\nwith contextlib.suppress(OSError):\n    p.chmod(0o600)\n```\n\nVerified under `umask 022`: directory `0o700`, file `0o600`, no group/other access.\n\n### Workarounds\n\nIf you cannot upgrade immediately, restrict the token store manually and keep it owner-only:\n\n```bash\nchmod 700 ~/.garminconnect\nchmod 600 ~/.garminconnect/garmin_tokens.json\n```\n\n### Remediation\n\n1. **Upgrade** to `garminconnect >= 0.3.5`:\n   ```bash\n   pip install --upgrade garminconnect\n   ```\n2. **Fix any token file already on disk** — upgrading only tightens permissions\n   on the *next* write, so an existing world-readable file stays exposed until\n   then:\n   ```bash\n   chmod 600 ~/.garminconnect/garmin_tokens.json\n   # or remove it and log in again to mint a fresh token store\n   ```\n3. **If the file was exposed on a shared host, treat the refresh token as\n   compromised.** Re-authenticate (delete the token store and log in again) so\n   a new token is issued; consider the previously stored token potentially\n   read by others until rotated.\n\n### Credit\n\nReported by **EQSTLab** via a private security advisory. garminconnect thanks them for the detailed, responsible disclosure.","published":"2026-07-15T17:33:00Z","modified":"2026-07-23T15:11:39.561071147Z","cvss":{"score":8.4,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"garminconnect","fixedVersion":"0.3.5"}],"fix":{"url":"https://github.com/cyberjunky/python-garminconnect/commit/77a3837f1f79d486663c9646438e70e8319e1a48","label":"cyberjunky/python-garminconnect@77a3837"},"references":[{"type":"WEB","url":"https://github.com/cyberjunky/python-garminconnect/security/advisories/GHSA-wjhr-76vg-2hvc"},{"type":"WEB","url":"https://github.com/cyberjunky/python-garminconnect/commit/77a3837f1f79d486663c9646438e70e8319e1a48"},{"type":"WEB","url":"https://github.com/cyberjunky/python-garminconnect/commit/f74174a5647e1af78eca1f8f3a0aa5dc5a899947"},{"type":"PACKAGE","url":"https://github.com/cyberjunky/python-garminconnect"},{"type":"WEB","url":"https://github.com/cyberjunky/python-garminconnect/releases/tag/0.3.5"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-23T15:11:39.561071147Z"}}