CVE-2026-45306: Pyload ng PyLoad Has Incomplete Fix For Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w727-595x-pc3r",
  "modified" : "2026-06-09T10:19:36Z",
  "published" : "2026-05-14T20:17:27Z",
  "aliases" : [ "CVE-2026-45306" ],
  "summary" : "pyLoad Has Incomplete Fix for CVE-2026-33509 -storage_folder Bypass via Session Directory in pyLoad",
  "details" : "## Summary\nThe fix for CVE-2026-33509 prevents setting `storage_folder` inside `PKGDIR` or `userdir`, but does NOT protect the Flask session directory (`/tmp/pyLoad/flask`). An authenticated attacker can set `storage_folder` to the session directory and download session files of other users via `/files/get/`, leading to account takeover.\n\n## Details\n\nThe fix in `src/pyload/core/api/__init__.py`:\n\n```python\ndirectories = [PKGDIR, userdir]\nif any(directories[0].startswith(d) for d in directories[1:]):\n    return  # blocked\n```\n\nBut the Flask session directory is:\n```python\nsession_storage_path = os.path.join(api.get_cachedir(), \"flask\")\n# = /tmp/pyLoad/flask  ← NOT blocked by fix\n```\n\n## Attack Chain\n\n1. Attacker (admin) sets `storage_folder = /tmp/pyLoad/flask`\n2. Fix does NOT block this — `/tmp/pyLoad/flask` not inside `PKGDIR` or `userdir`\n3. Attacker requests `GET /files/get/<victim_session_filename>`\n4. `send_from_directory('/tmp/pyLoad/flask', session_file)` serves victim's session\n5. Attacker uses stolen session → **Account Takeover**\n\n## PoC\n\n<img width=\"592\" height=\"408\" alt=\"POC\" src=\"https://github.com/user-attachments/assets/936b9f56-325b-437d-9edd-e0d5bb995187\" />\n\n```python\nimport os\n\nPKGDIR = \"/usr/lib/python3/dist-packages/pyload\"\nuserdir = os.path.expanduser(\"~/.pyload\")\nsession_dir = \"/tmp/pyLoad/flask\"\n\ncorrect_case = lambda x: x\ndirectories = [\n    correct_case(os.path.join(os.path.realpath(d), \"\"))\n    for d in [session_dir, PKGDIR, userdir]\n]\nblocked = any(directories[0].startswith(d) for d in directories[1:])\n\nprint(f\"Fix blocks session_dir: {blocked}\")\n# Output: Fix blocks session_dir: False  ← BYPASS CONFIRMED\n```\n\n## Impact\nAuthenticated admin can steal sessions of other users → Account Takeover.\n\n## Suggested Fix\n```python\nblocked_dirs = [PKGDIR, userdir, api.get_cachedir()]\ndirectories = [\n    os.path.join(os.path.realpath(d), \"\")\n    for d in [value] + blocked_dirs\n]\nif any(directories[0].startswith(d) for d in directories[1:]):\n    return\n```",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pyload-ng"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.5.0b3.dev99"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/security/advisories/GHSA-w727-595x-pc3r"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45306"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-r7mc-x6x7-cqxx"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pyload/pyload"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-706" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T20:17:27Z",
    "nvd_published_at" : "2026-05-28T18:16:34Z"
  }
}