Vulnerability-Lookup

SUSE-SU-2026:23523-1

Vulnerability from csaf_suse - Published: 2026-09-07 09:21 - Updated: 2026-09-17 16:22

Summary

Security update for python-tornado6

Severity

Important

Notes

Title of the patch: Security update for python-tornado6

Description of the patch: This update for python-tornado6 fixes the following issue: - CVE-2026-82397: an unauthenticated request body containing millions of separator-delimited fields can synchronously stall the single-threaded event loop and delay every connection (bsc#1277725).

Patchnames: SUSE-SLE-Micro-6.1-711

CVE-2026-82397

7.5 (High)


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

Affected products

Recommended 4 products

Product	Version	Remediation
Unresolved product id: SUSE Linux Micro 6.1:python311-tornado6-0:6.4-slfo.1.1_7.1.aarch64	—	Vendor Fix
Unresolved product id: SUSE Linux Micro 6.1:python311-tornado6-0:6.4-slfo.1.1_7.1.ppc64le	—	Vendor Fix
Unresolved product id: SUSE Linux Micro 6.1:python311-tornado6-0:6.4-slfo.1.1_7.1.s390x	—	Vendor Fix
Unresolved product id: SUSE Linux Micro 6.1:python311-tornado6-0:6.4-slfo.1.1_7.1.x86_64	—	Vendor Fix

Threats

Impact important

References

8 references

URL	Category
https://www.suse.com/support/security/rating/	external
https://ftp.suse.com/pub/projects/security/csaf/s…	self
https://www.suse.com/support/update/announcement/…	self
https://lists.suse.com/pipermail/sle-security-upd…	self
https://bugzilla.suse.com/1277725	self
https://www.suse.com/security/cve/CVE-2026-82397/	self
https://www.suse.com/security/cve/CVE-2026-82397	external
https://bugzilla.suse.com/1277725	external

JSON

To clipboard

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      "title": "CVE-2026-82397"
    }
  ]
}

CVE-2026-82397 (GCVE-0-2026-82397)

Vulnerability from cvelistv5 – Published: 2026-08-31 21:28 – Updated: 2026-09-02 17:39

Title

Tornado: Urlencoded body parsing omits max_num_fields, so one request can stall the event loop

Summary

Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parses application/x-www-form-urlencoded request bodies with urllib.parse.parse_qs in tornado/escape.py without passing max_num_fields. RequestHandler._execute in tornado/web.py parses the body before handler dispatch through HTTPServerRequest._parse_body and parse_body_arguments in tornado/httputil.py, so an unauthenticated request body containing millions of separator-delimited fields can synchronously stall the single-threaded event loop and delay every connection. The body is bounded only by max_buffer_size, which defaults to 104857600 bytes. This issue is fixed in version 6.5.8.

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 2026-09-02 17:39 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-1284 - Improper Validation of Specified Quantity in Input

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/tornadoweb/tornado/security/ad…	x_refsource_CONFIRM
https://github.com/tornadoweb/tornado/pull/3704	x_refsource_MISC
https://github.com/tornadoweb/tornado/commit/8d63…	x_refsource_MISC
https://github.com/tornadoweb/tornado/releases/ta…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
tornadoweb	tornado	Affected: < 6.5.8

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-82397",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-02T17:39:28.982654Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-02T17:39:41.238Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "tornado",
          "vendor": "tornadoweb",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.5.8"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parses application/x-www-form-urlencoded request bodies with urllib.parse.parse_qs in tornado/escape.py without passing max_num_fields. RequestHandler._execute in tornado/web.py parses the body before handler dispatch through HTTPServerRequest._parse_body and parse_body_arguments in tornado/httputil.py, so an unauthenticated request body containing millions of separator-delimited fields can synchronously stall the single-threaded event loop and delay every connection. The body is bounded only by max_buffer_size, which defaults to 104857600 bytes. This issue is fixed in version 6.5.8."
        }
      ],
      "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": [
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          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "CWE-400: Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-1284",
              "description": "CWE-1284: Improper Validation of Specified Quantity in Input",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-31T21:28:13.958Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-mpf4-983q-p7j4",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-mpf4-983q-p7j4"
        },
        {
          "name": "https://github.com/tornadoweb/tornado/pull/3704",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/tornadoweb/tornado/pull/3704"
        },
        {
          "name": "https://github.com/tornadoweb/tornado/commit/8d6363ed7b69d5f0da806efe34d256627a2191de",
          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/tornadoweb/tornado/commit/8d6363ed7b69d5f0da806efe34d256627a2191de"
        },
        {
          "name": "https://github.com/tornadoweb/tornado/releases/tag/v6.5.8",
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          "url": "https://github.com/tornadoweb/tornado/releases/tag/v6.5.8"
        }
      ],
      "source": {
        "advisory": "GHSA-mpf4-983q-p7j4",
        "discovery": "UNKNOWN"
      },
      "title": "Tornado: Urlencoded body parsing omits max_num_fields, so one request can stall the event loop"
    }
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  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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    "datePublished": "2026-08-31T21:28:13.958Z",
    "dateReserved": "2026-08-28T22:00:43.512Z",
    "dateUpdated": "2026-09-02T17:39:41.238Z",
    "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.

Detection rules are retrieved from Rulezet.

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.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.