CVE-2026-40347

{
  "id": "CVE-2026-40347",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-18T00:16:38.520",
  "lastModified": "2026-10-26T21:10:00.170",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Python-Multipart is a streaming multipart parser for Python. Versions prior to 0.0.26 have a denial of service vulnerability when parsing crafted `multipart/form-data` requests with large preamble or epilogue sections. Upgrade to version 0.0.26 or later, which skips ahead to the next boundary candidate when processing leading CR/LF data and immediately discards epilogue data after the closing boundary."
    },
    {
      "lang": "es",
      "value": "Python-Multipart es un analizador multipart de streaming para Python. Las versiones anteriores a la 0.0.26 tienen una vulnerabilidad de denegación de servicio al analizar solicitudes ’multipart/form-data’ especialmente diseñadas con secciones de preámbulo o epílogo grandes. Actualice a la versión 0.0.26 o posterior, que salta al siguiente candidato de límite al procesar datos CR/LF iniciales y descarta inmediatamente los datos del epílogo después del límite de cierre."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Kludex",
          "product": "python-multipart",
          "versions": [
            {
              "version": "< 0.0.26",
              "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:L",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-20T15:46:36.258461Z",
          "id": "CVE-2026-40347",
          "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-400"
        },
        {
          "lang": "en",
          "value": "CWE-834"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:fastapiexpert:python-multipart:*:*:*:*:*:python:*:*",
              "versionEndExcluding": "0.0.26",
              "matchCriteriaId": "74822284-E6D0-44D0-BED4-8D925B664EE0"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/Kludex/python-multipart/releases/tag/0.0.26",
      "source": "[email protected]",
      "tags": [
        "Product",
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pj",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}