Tornado 6.5.6 security fixes

{
  "id": "2bd7f85c6ae7d260c2406d4ddde717134489573c6786d7e14def79681e8df79d",
  "url": "https://github.com/tornadoweb/tornado/releases/tag/v6.5.6",
  "method": "llm",
  "payload": {
    "kind": "patch",
    "title": "Tornado 6.5.6 security fixes",
    "summary": "Tornado 6.5.6 includes security fixes for redirect handling and response-size enforcement in SimpleAsyncHTTPClient, along with fixes to the C extension and OpenIDMixin response parsing.",
    "evidence": "v6.5.6: What's new in Tornado 6.5.6\n\nMay 27, 2026 Security fixes - ``SimpleAsyncHTTPClient`` now strips the ``Authorization`` and ``Cookie`` headers from the request when following a redirect to a different origin. This matches the default behavior of ``CurlAsyncHTTPClient``. Applications that need different behavior here can set ``follow_redirects=False`` and handle redirects manually. Thanks to [Yannick Wang](https://github.com/noobone123) for being first to report this issue, as well as additional reporters [Kai Aizen](https://github.com/SnailSploit), [HunSec](https://github.com/0xHunSec), and [Thai Son Dinh](https://github.com/sondt99). - ``SimpleAsyncHTTPClient`` now enforces ``max_body_size`` on the decompressed size of the response, rather than the compressed size. This prevents a denial-of-service attack via a very large compressed response. Thanks to [Yuichiro Kedashiro](https://github.com/yuui25) for reporting this issue. - Fixed a bug in the C extension that could have read",
    "products": [
      {
        "name": {
          "value": "Tornado",
          "evidence": "Release notes from tornado\nv6.5.6: What's new in Tornado 6.5.6"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.5.6",
            "evidence": "v6.5.6: What's new in Tornado 6.5.6"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "github-tornadoweb-tornado",
  "document_id": 22768,
  "published_at": "2026-05-27T15:19:37+00:00"
}