GHSA-3X9G-8VMP-WQVF

Vulnerability from github – Published: 2026-06-15 20:20 – Updated: 2026-06-15 20:20
VLAI
Summary
Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient
Details

Summary

When SimpleAsyncHTTPClient follows a 3xx redirect, it shallow-copies the original HTTPRequest, rewrites the URL, decrements max_redirects, and removes only the Host header. It does not clear Authorization, auth_username, auth_password, or auth_mode when the redirect target changes origin.

As a result, credentials intended for one origin can be forwarded to a different origin when follow_redirects=True, which is the default.

Beginning in Tornado 6.5.6, SimpleAsyncHTTPClient matches the default behavior of libcurl (and therefore CurlAsyncHTTPClient): When a redirect changes the scheme, host, or port of the url, the Authorization and Cookie headers will be removed when following the redirect.

Severity
7.7 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "tornado"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.5.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49853"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-15T20:20:00Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Summary\n\nWhen SimpleAsyncHTTPClient follows a 3xx redirect, it shallow-copies the original HTTPRequest, rewrites the URL, decrements max_redirects, and removes only the Host header. It does not clear Authorization, auth_username, auth_password, or auth_mode when the redirect target changes origin.\n\nAs a result, credentials intended for one origin can be forwarded to a different origin when follow_redirects=True, which is the default.\n\nBeginning in Tornado 6.5.6, `SimpleAsyncHTTPClient` matches the default behavior of `libcurl` (and therefore `CurlAsyncHTTPClient`): When a redirect changes the scheme, host, or port of the url, the `Authorization` and `Cookie` headers will be removed when following the redirect.",
  "id": "GHSA-3x9g-8vmp-wqvf",
  "modified": "2026-06-15T20:20:00Z",
  "published": "2026-06-15T20:20:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-3x9g-8vmp-wqvf"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tornadoweb/tornado"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient"
}



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