CVE-2026-49855

{
  "id": "CVE-2026-49855",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-14T21:17:02.437",
  "lastModified": "2026-10-24T21:10:00.130",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip decompression routines processed limited-size chunks but did not enforce an overall limit on accumulated decompressed chunks, allowing a malicious server accessed by SimpleAsyncHTTPClient or an HTTPServer configured with decompress_request=True to consume effectively unlimited memory. This issue is fixed in version 6.5.6."
    },
    {
      "lang": "es",
      "value": "Tornado es un framework web de Python y una biblioteca de red asíncrona. Antes de la versión 6.5.6, las rutinas de descompresión gzip de Tornado procesaban fragmentos de tamaño limitado pero no aplicaban un límite general a los fragmentos descomprimidos acumulados, lo que permitía a un servidor malicioso accedido por SimpleAsyncHTTPClient o un HTTPServer configurado con decompress_request=True consumir memoria de forma efectivamente ilimitada. Este problema está solucionado en la versión 6.5.6."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "tornadoweb",
          "product": "tornado",
          "versions": [
            {
              "version": "< 6.5.6",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-16T14:55:32.574509Z",
          "id": "CVE-2026-49855",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-409"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/tornadoweb/tornado/commit/ff808b33adc52d89a549376a5e3628e92abbc8ff",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/tornadoweb/tornado/pull/3626",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-mgf9-4vpg-hj56",
      "source": "[email protected]"
    }
  ]
}