{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "6.5.8"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "DESCRIPTION"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "a55abe3e3bf59994f29b2f7084c46341f0d4f6a7"
            }
          ],
          "repo": "https://github.com/tornadoweb/tornado",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-8423-8fgw-73vq"
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91990.json"
  },
  "details": "Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service.",
  "id": "CVE-2026-91990",
  "modified": "2026-09-17T03:30:43.174056643Z",
  "published": "2026-09-15T15:18:31.715Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91990.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-8423-8fgw-73vq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91990"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/tornado-before-6.5.8-memory-amplification-dos-via-multipart"
    }
  ],
  "schema_version": "1.9.0",
  "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Tornado before 6.5.8 Memory Amplification DoS via multipart"
}