Vulnerability-Lookup

PYSEC-2023-221

Vulnerability from pysec - Published: 2023-10-25 18:17 - Updated: 2023-11-08 18:38

Details

Werkzeug is a comprehensive WSGI web application library. If an upload of a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. This vulnerability has been patched in version 3.0.1.

Severity

7.5 (High)


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

Impacted products

Name	purl
werkzeug	pkg:pypi/werkzeug

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "werkzeug",
        "purl": "pkg:pypi/werkzeug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "f3c803b3ade485a45f12b6d6617595350c0f03e2"
            },
            {
              "fixed": "f2300208d5e2a5076cbbb4c2aad71096fd040ef9"
            }
          ],
          "repo": "https://github.com/pallets/werkzeug",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.3.8"
            },
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1",
        "0.10",
        "0.10.1",
        "0.10.2",
        "0.10.3",
        "0.10.4",
        "0.11",
        "0.11.1",
        "0.11.10",
        "0.11.11",
        "0.11.12",
        "0.11.13",
        "0.11.14",
        "0.11.15",
        "0.11.2",
        "0.11.3",
        "0.11.4",
        "0.11.5",
        "0.11.6",
        "0.11.7",
        "0.11.8",
        "0.11.9",
        "0.12",
        "0.12.1",
        "0.12.2",
        "0.13",
        "0.14",
        "0.14.1",
        "0.15.0",
        "0.15.1",
        "0.15.2",
        "0.15.3",
        "0.15.4",
        "0.15.5",
        "0.15.6",
        "0.16.0",
        "0.16.1",
        "0.2",
        "0.3",
        "0.3.1",
        "0.4",
        "0.4.1",
        "0.5",
        "0.5.1",
        "0.6",
        "0.6.1",
        "0.6.2",
        "0.7",
        "0.7.1",
        "0.7.2",
        "0.8",
        "0.8.1",
        "0.8.2",
        "0.8.3",
        "0.9",
        "0.9.1",
        "0.9.2",
        "0.9.3",
        "0.9.4",
        "0.9.5",
        "0.9.6",
        "1.0.0",
        "1.0.0rc1",
        "1.0.1",
        "2.0.0",
        "2.0.0rc1",
        "2.0.0rc2",
        "2.0.0rc3",
        "2.0.0rc4",
        "2.0.0rc5",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.1.0",
        "2.1.1",
        "2.1.2",
        "2.2.0",
        "2.2.0a1",
        "2.2.1",
        "2.2.2",
        "2.2.3",
        "2.3.0",
        "2.3.1",
        "2.3.2",
        "2.3.3",
        "2.3.4",
        "2.3.5",
        "2.3.6",
        "2.3.7",
        "3.0.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2023-46136",
    "GHSA-hrfv-mqp8-q5rw"
  ],
  "details": "Werkzeug is a comprehensive WSGI web application library. If an upload of a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. This vulnerability has been patched in version 3.0.1.",
  "id": "PYSEC-2023-221",
  "modified": "2023-11-08T18:38:34.170214Z",
  "published": "2023-10-25T18:17:00Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2023-46136 (GCVE-0-2023-46136)

Vulnerability from cvelistv5 – Published: 2023-10-24 23:48 – Updated: 2026-05-20 22:17

Title

Werkzeug vulnerable to high resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning

Summary

Werkzeug is a comprehensive WSGI web application library. In versions on the 3.x branch prior to 3.0.1 and on the 2.x branch prior to 2.3.8, if an upload of a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. This vulnerability has been patched in version 3.0.1 and 2.3.8.

Severity

8 (High)


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

CWE

CWE-407 - Inefficient Algorithmic Complexity
CWE-400 - Uncontrolled Resource Consumption

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/pallets/werkzeug/security/advi…	x_refsource_CONFIRM
https://github.com/pallets/werkzeug/commit/f3c803…	x_refsource_MISC
https://security.netapp.com/advisory/ntap-2023112…	x_transferred

Impacted products

1 product

Vendor	Product	Version
pallets	werkzeug	Affected: >= 3.0.0, < 3.0.1 Affected: >= 2.0.0rc1, < 2.3.8

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-02T20:37:39.469Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "name": "https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw",
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw"
          },
          {
            "name": "https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2",
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20231124-0008/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "werkzeug",
          "vendor": "pallets",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.0.1"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.0.0rc1, \u003c 2.3.8"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Werkzeug is a comprehensive WSGI web application library. In versions on the 3.x branch prior to 3.0.1 and on the 2.x branch prior to 2.3.8, if an upload of a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. This vulnerability has been patched in version 3.0.1 and 2.3.8."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-407",
              "description": "CWE-407: Inefficient Algorithmic Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "CWE-400: Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-20T22:17:43.259Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw"
        },
        {
          "name": "https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2"
        }
      ],
      "source": {
        "advisory": "GHSA-hrfv-mqp8-q5rw",
        "discovery": "UNKNOWN"
      },
      "title": "Werkzeug vulnerable to high resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2023-46136",
    "datePublished": "2023-10-24T23:48:56.960Z",
    "dateReserved": "2023-10-16T17:51:35.574Z",
    "dateUpdated": "2026-05-20T22:17:43.259Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-HRFV-MQP8-Q5RW

Vulnerability from github – Published: 2023-10-25 14:22 – Updated: 2026-05-20 22:21

Summary

Werkzeug DoS: High resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning

Details

Werkzeug multipart data parser needs to find a boundary that may be between consecutive chunks. That's why parsing is based on looking for newline characters. Unfortunately, code looking for partial boundary in the buffer is written inefficiently, so if we upload a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer.

This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. The amount of RAM required can trigger an out of memory kill of the process. If many concurrent requests are sent continuously, this can exhaust or kill all available workers.

Severity

5.7 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "Werkzeug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "Werkzeug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0rc1"
            },
            {
              "fixed": "2.3.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-46136"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-787"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-10-25T14:22:59Z",
    "nvd_published_at": "2023-10-25T18:17:36Z",
    "severity": "MODERATE"
  },
  "details": "Werkzeug multipart data parser needs to find a boundary that may be between consecutive chunks. That\u0027s why parsing is based on looking for newline characters. Unfortunately, code looking for partial boundary in the buffer is written inefficiently, so if we upload a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer.\n\nThis allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. The amount of RAM required can trigger an out of memory kill of the process. If many concurrent requests are sent continuously, this can exhaust or kill all available workers.",
  "id": "GHSA-hrfv-mqp8-q5rw",
  "modified": "2026-05-20T22:21:18Z",
  "published": "2023-10-25T14:22:59Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-46136"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/commit/b1916c0c083e0be1c9d887ee2f3d696922bfc5c1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/commit/cbb446fdcada7685fce936ded01b76c08dbd6eb5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/commit/f2300208d5e2a5076cbbb4c2aad71096fd040ef9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pallets/werkzeug"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/werkzeug/PYSEC-2023-221.yaml"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20231124-0008"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Werkzeug DoS: High resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning"
}

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.

Action not permitted

PYSEC-2023-221

CVE-2023-46136 (GCVE-0-2023-46136)

GHSA-HRFV-MQP8-Q5RW

Tags

Sightings

Nomenclature

Related by attack behaviour