Vulnerability-Lookup

OESA-2026-1018 (CVE-2025-67726)

Vulnerability from osv_openeuler – Published: 2026-01-09 11:10 – Updated: 2026-08-06 11:10 – Source website

Summary

python-tornado security update

Details

Tornado is an open source version of the scalable, non-blocking web server and tools.

Security Fix(es):

Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in multipart/form-data and repeatedly calls string.count() within a nested loop while processing quoted semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a Content-Disposition header, the server's CPU usage increases quadratically (O(n²)) during parsing. Due to Tornado's single event loop architecture, a single malicious request can cause the entire server to become unresponsive for an extended period. This issue is fixed in version 6.5.3.(CVE-2025-67726)

Severity

7.5 (High)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

URL

Type

	https://www.openeuler.org/zh/security/security-bu…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2025-67726	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "python-tornado-debuginfo-6.5-2.oe2403sp3.aarch64.rpm",
          "python-tornado-debugsource-6.5-2.oe2403sp3.aarch64.rpm",
          "python-tornado-help-6.5-2.oe2403sp3.aarch64.rpm",
          "python3-tornado-6.5-2.oe2403sp3.aarch64.rpm"
        ],
        "src": [
          "python-tornado-6.5-2.oe2403sp3.src.rpm"
        ],
        "x86_64": [
          "python-tornado-debuginfo-6.5-2.oe2403sp3.x86_64.rpm",
          "python-tornado-debugsource-6.5-2.oe2403sp3.x86_64.rpm",
          "python-tornado-help-6.5-2.oe2403sp3.x86_64.rpm",
          "python3-tornado-6.5-2.oe2403sp3.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:24.03-LTS-SP3",
        "name": "python-tornado",
        "purl": "pkg:rpm/openEuler/python-tornado\u0026distro=openEuler-24.03-LTS-SP3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.5-2.oe2403sp3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "High"
  },
  "details": "Tornado is an open source version of the scalable, non-blocking web server and tools.\r\n\r\nSecurity Fix(es):\n\nTornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in multipart/form-data and repeatedly calls string.count() within a nested loop while processing quoted semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a Content-Disposition header, the server\u0026apos;s CPU usage increases quadratically (O(n\u00b2)) during parsing. Due to Tornado\u0026apos;s single event loop architecture, a single malicious request can cause the entire server to become unresponsive for an extended period. This issue is fixed in version 6.5.3.(CVE-2025-67726)",
  "id": "OESA-2026-1018",
  "modified": "2026-08-06T11:10:03Z",
  "published": "2026-01-09T11:10:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1018"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-67726"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "python-tornado security update",
  "upstream": [
    "CVE-2025-67726"
  ]
}

CVE-2025-67726 (GCVE-0-2025-67726)

Vulnerability from cvelistv5 – Published: 2025-12-12 06:13 – Updated: 2025-12-18 18:48

Title

Tornado is Vulnerable to Quadratic DoS via Crafted Multipart Parameters

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-12-18 18:47 UTC

CWE

CWE-834 - Excessive Iteration
CWE-400 - Uncontrolled Resource Consumption

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/tornadoweb/tornado/security/ad…	x_refsource_CONFIRM
https://github.com/tornadoweb/tornado/commit/7714…	x_refsource_MISC
https://github.com/tornadoweb/tornado/releases/ta…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
tornadoweb	tornado	Affected: < 6.5.3

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-67726",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-12-18T18:47:53.473225Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-12-18T18:48:49.007Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "tornado",
          "vendor": "tornadoweb",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.5.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in multipart/form-data and repeatedly calls string.count() within a nested loop while processing quoted semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a Content-Disposition header, the server\u0027s CPU usage increases quadratically (O(n\u00b2)) during parsing. Due to Tornado\u0027s single event loop architecture, a single malicious request can cause the entire server to become unresponsive for an extended period. This issue is fixed in version 6.5.3."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-834",
              "description": "CWE-834: Excessive Iteration",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "CWE-400: Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-12T06:13:51.336Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-jhmp-mqwm-3gq8",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-jhmp-mqwm-3gq8"
        },
        {
          "name": "https://github.com/tornadoweb/tornado/commit/771472cfdaeebc0d89a9cc46e249f8891a6b29cd",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/tornadoweb/tornado/commit/771472cfdaeebc0d89a9cc46e249f8891a6b29cd"
        },
        {
          "name": "https://github.com/tornadoweb/tornado/releases/tag/v6.5.3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/tornadoweb/tornado/releases/tag/v6.5.3"
        }
      ],
      "source": {
        "advisory": "GHSA-jhmp-mqwm-3gq8",
        "discovery": "UNKNOWN"
      },
      "title": "Tornado is Vulnerable to Quadratic DoS via Crafted Multipart Parameters"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2025-67726",
    "datePublished": "2025-12-12T06:13:51.336Z",
    "dateReserved": "2025-12-10T19:25:20.819Z",
    "dateUpdated": "2025-12-18T18:48:49.007Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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OESA-2026-1018 (CVE-2025-67726)

CVE-2025-67726 (GCVE-0-2025-67726)

Tags

Sightings

Nomenclature

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