CVE-2026-54283

{
  "id": "CVE-2026-54283",
  "sourceIdentifier": "[email protected]",
  "published": "2026-06-22T18:16:46.943",
  "lastModified": "2026-10-25T23:10:00.167",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Starlette is a lightweight ASGI framework/toolkit. From 0.4.1 until 1.3.1, request.form() accepts max_fields and max_part_size to bound resource consumption while parsing form data. These limits are enforced for multipart/form-data, but silently ignored for application/x-www-form-urlencoded. An unauthenticated attacker can therefore send a urlencoded body with an arbitrarily large number of fields or an arbitrarily large field, even when the application configured limits it believed would apply. This vulnerability is fixed in 1.3.1."
    },
    {
      "lang": "es",
      "value": "Starlette es un framework/toolkit ASGI ligero. Desde la versión 0.4.1 hasta la 1.3.1, request.form() acepta max_fields y max_part_size para limitar el consumo de recursos al analizar datos de formulario. Estos límites se aplican para multipart/form-data, pero se ignoran silenciosamente para application/x-www-form-urlencoded. Un atacante no autenticado puede, por lo tanto, enviar un cuerpo urlencoded con un número arbitrariamente grande de campos o un campo arbitrariamente grande, incluso cuando la aplicación configuró límites que creía que se aplicarían. Esta vulnerabilidad se corrige en la versión 1.3.1."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Kludex",
          "product": "starlette",
          "versions": [
            {
              "version": ">= 0.4.1, < 1.3.1",
              "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:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-06-23T16:06:30.546768Z",
          "id": "CVE-2026-54283",
          "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-770"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:encode:starlette:*:*:*:*:*:python:*:*",
              "versionStartIncluding": "0.4.1",
              "versionEndExcluding": "1.3.1",
              "matchCriteriaId": "2FDB02B2-DCF6-4F2C-B06B-78C015D16494"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/Kludex/starlette/security/advisories/GHSA-82w8-qh3p-5jfq",
      "source": "[email protected]",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ]
    }
  ]
}