GHSA-68w4-83fh-f2w8: pyload-ng Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-68w4-83fh-f2w8",
  "modified" : "2026-10-09T17:09:15Z",
  "published" : "2026-10-09T17:09:15Z",
  "aliases" : [ ],
  "summary" : "pyload-ng: getUserData/get_userdata exposed at Perms.ANY allow any authenticated account to brute-force the administrator password",
  "details" : "## Summary\n\n`Api.getUserData` (legacy) and `Api.get_userdata` are declared with `@permission(Perms.ANY)` and are reachable at `/api/getUserData` and `/api/get_userdata`. Because `Perms.ANY == 0` and pyLoad's permission check is a bitmask AND, that gate is a no-op: **every authenticated account passes, including one holding zero permission bits.**\n\nBoth methods are thin wrappers around `check_auth()`, which the maintainers deliberately restricted to administrators by omitting `@permission` (no entry in `perm_map`, so `is_authorized()` returns `False` for non-admins). The wrappers undo that protection.\n\nAn attacker holding the lowest-privileged account in the system therefore has a clean binary oracle on the **administrator password**, with no account lockout anywhere in the codebase, and with the 100 req/min rate limiter bypassable by rotating `X-Forwarded-For`.\n\n## Affected code\n\n`src/pyload/core/api/__init__.py:1446` and `:1464`\n\n```python\n    #: Old API\n    @permission(Perms.ANY)\n    @get\n    def getUserData(self, username: str, password: str) -> OldUserData:\n        \"\"\"\n        similar to `check_auth` but returns UserData type.\n        \"\"\"\n        user = self.check_auth(username, password)\n        ...\n\n    @permission(Perms.ANY)\n    @get\n    def get_userdata(self, username: str, password: str) -> UserData:\n        user = self.check_auth(username, password)\n        ...\n```\n\n## Root cause\n\n`src/pyload/core/api/__init__.py:57`\n\n```python\nclass Perms(IntFlag):\n    ANY = 0  #: requires no permission, but login\n```\n\n`src/pyload/core/api/__init__.py:108`\n\n```python\ndef has_permission(user_perms: Perms, required_perms: Perms):\n    return required_perms == (user_perms & required_perms)\n```\n\nFor `required_perms == 0` this evaluates to `0 == (user_perms & 0)` → `0 == 0` → **always `True`**. The `@permission(Perms.ANY)` gate therefore admits every authenticated principal regardless of which permission bits they hold.\n\nContrast with the intended admin-only primitive, `src/pyload/core/api/__init__.py:1396`:\n\n```python\n    @legacy(\"checkAuth\")\n    @get\n    def check_auth(self, username: str, password: str) -> dict[str, Any]:\n```\n\n`check_auth` has **no** `@permission`; `is_authorized()` at `api/__init__.py:1430` returns `False` for non-admins. The two wrappers carry `Perms.ANY` and restore access for everyone.\n\nBecause both wrappers also carry `@get`, they are placed in `method_map` and are directly routable via `/api/<func>`.\n\n## Amplifiers\n\n**1. No lockout.** There is no failed-login counter, delay, or ban anywhere in the codebase. A failed guess costs the attacker only one PBKDF2 computation.\n\n**2. Rate limiting is bypassable.** `/api/*` applies `rate_limit(count=100, period=60)` (`src/pyload/webui/app/blueprints/api_blueprint.py:25`), which buckets on a fully client-controlled header (`src/pyload/webui/app/helpers.py:446`):\n\n```python\nclient_ip = flask.request.headers.get(\"X-Forwarded-For\", \"\").split(\",\")[0].strip() \\\n    or flask.request.remote_addr\n```\n\nRotating `X-Forwarded-For` per request yields a fresh bucket each time. Notably, `is_loopback_request()` in the **same file** (`helpers.py:288-294`) explicitly treats the presence of `X-Forwarded-For` / `X-Real-IP` / `Forwarded` as untrustworthy — the same guard was evidently not applied inside `rate_limit()`.\n\n## Impact\n\nOnline brute force of the administrator account leading to full administrative takeover. A successful response additionally discloses the target account's `id`, `name`, `email`, `role`, and `permission` bits.\n\n## Proof of concept\n\nVerified against 0.5.0b3, commit `a5b008958`.\n\nSetup: stock instance with admin `pyload`, plus a non-admin user `bob` created with `role=USER` and `permission=0`.\n\n**Step 1 — establish that `bob` is genuinely unprivileged:**\n\n```\nGET /api/checkAuth?username=pyload&password=pyload   ->  401 {\"error\": \"Access denied\"}\nGET /api/getAllUserData                              ->  401 {\"error\": \"Access denied\"}\n```\n\n**Step 2 — the flaw. Same user, same session, `Perms.ANY` gate:**\n\n```\nGET /api/getUserData?username=pyload&password=WRONG\n  -> 200 {\"name\": null, \"email\": null, \"role\": null, \"permission\": null, \"template_name\": null}\n\nGET /api/getUserData?username=pyload&password=pyload\n  -> 200 {\"name\": \"pyload\", \"email\": \"\", \"role\": 0, \"permission\": 0, \"template_name\": \"default\"}\n```\n\n`role: 0` is `Role.ADMIN`. `get_userdata` behaves identically. This is a perfect yes/no oracle.\n\n**Step 3 — measured brute force and recovery.** Run as `bob` (`permission = 0`), admin password set to a 2-character value, `X-Forwarded-For` rotated on every request:\n\n```\nattempts         : 667\nelapsed          : 39.7s   (16.8 guesses/sec)\n429 rate-limits  : 0\naccount lockout  : NONE - same session authenticated throughout\nRECOVERED SECRET : 'zq'   (true value 'zq')   match=True\n```\n\n**Step 4 — full takeover with the recovered secret:**\n\n```\nPOST /login as pyload/<recovered>       ->  HTTP 302  (authenticated as admin)\nGET  /api/getAllUserData (admin-only)  ->  HTTP 200  (full user dump)\n```\n\nMeasured throughput is 17-47 guesses/sec/thread. The only bound is PBKDF2-HMAC-SHA256 at 100,000 iterations in `src/pyload/core/database/user_database.py:14`, not any rate limit.\n\n## Suggested remediation\n\n- Remove `@permission(Perms.ANY)` from `getUserData` and `get_userdata`, or drop them entirely — they are legacy compatibility shims, and modern callers already use the admin-only `check_auth`.\n- Structurally: `Perms.ANY = 0` makes `has_permission()` vacuous, so **any** method decorated `@permission(Perms.ANY)` silently becomes public to every logged-in user. Give `ANY` a real bit value, or handle it explicitly in `has_permission()` as \"requires an authenticated session\".\n- Do not trust `X-Forwarded-For` unless a trusted-proxy deployment is explicitly configured. Otherwise bucket `rate_limit()` on `request.remote_addr`, or add the same guard `is_loopback_request()` already uses.\n- Add per-account failed-authentication throttling or lockout.\n- Consider `hmac.compare_digest()` in `_check_password()` (`src/pyload/core/database/user_database.py:61` uses a plain `==` on the derived hash, contradicting the \"always use compare_digest\" guidance two files away).\n\n## Notes for triage\n\nThere is no `0.5.0b3` release on PyPI. The `develop` branch auto-publishes dev builds (`setup.py:86` appends `.dev<build>` to the `VERSION` file); the newest at time of testing was `0.5.0b3.dev101`. The `Perms.ANY = 0` design is long-standing, but only the `0.5.0b3.dev*` line was verified here — please confirm whether `0.5.0b2.*` and `0.4.x` are affected before finalizing the version range.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pyload-ng"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.5.0b3.dev1"
      }, {
        "last_affected" : "0.5.0b3.dev101"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/security/advisories/GHSA-68w4-83fh-f2w8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/commit/b99d2a2f06135363ceb0aab16aac5025f138e658"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pyload/pyload"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-09T17:09:15Z",
    "nvd_published_at" : null
  }
}