CVE-2026-33806

Estado: ModificadaAlta (7.5)—

Impact:

Fastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped.

This is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442

Patches:

Upgrade to fastify v5.8.5 or later.

Workarounds:

None. Upgrade to the patched version.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.48%
Percentil entre todas las CVEs puntuadas: 40
Fecha de la puntuación: 6/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access85 %
Impacto principalT1565.002 Transmitted Data Manipulationimpact75 %

Aplicación web expuesta (AV:N, PR:N) que permite eludir validación de esquemas modificando headers HTTP, permitiendo inyectar datos malformados o manipulados sin detección (I:H en CVSS).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Encrypt Sensitive Information

Tecnologías afectadas (1)

Fastify — Fastify

CWE

CWE-1287
CWE-1289

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-33806",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-33806",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-04-15T14:02:12.644507Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      },
      {
        "type": "Secondary",
        "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
      "affectedData": [
        {
          "vendor": "fastify",
          "product": "fastify",
          "versions": [
            {
              "status": "affected",
              "version": "5.3.2",
              "lessThan": "5.8.5",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.8.5",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:npm/fastify",
          "defaultStatus": "unaffected"
        }
      ]
    },
    {
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
      "affectedData": [
        {
          "cpes": [
            "cpe:/a:redhat:enterprise_linux_ai:3"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux AI (RHEL AI) 3",
          "packageName": "rhelai3/bootc-cuda-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:enterprise_linux_ai:3"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux AI (RHEL AI) 3",
          "packageName": "rhelai3/bootc-rocm-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:enterprise_linux_ai:3"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux AI (RHEL AI) 3",
          "packageName": "rhelai3/disk-image-cuda-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift_ai"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift AI (RHOAI)",
          "packageName": "rhoai/odh-dashboard-rhel8",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift_ai"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift AI (RHOAI)",
          "packageName": "rhoai/odh-dashboard-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift_ai"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift AI (RHOAI)",
          "packageName": "rhoai/odh-mod-arch-gen-ai-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift_ai"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift AI (RHOAI)",
          "packageName": "rhoai/odh-mod-arch-maas-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift_ai"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift AI (RHOAI)",
          "packageName": "rhoai/odh-mod-arch-model-registry-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        },
        {
          "cpes": [
            "cpe:/a:redhat:openshift_devspaces:3"
          ],
          "vendor": "Red Hat",
          "product": "Red Hat OpenShift Dev Spaces",
          "packageName": "devspaces/dashboard-rhel9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-04-15T04:17:36.650",
  "references": [
    {
      "url": "https://cna.openjsf.org/security-advisories.html",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb"
    },
    {
      "url": "https://github.com/fastify/fastify/security/advisories/GHSA-mg2h-6x62-wpwc",
      "tags": [
        "Not Applicable"
      ],
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb"
    },
    {
      "url": "https://access.redhat.com/security/cve/CVE-2026-33806",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2458596",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    },
    {
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33806.json",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
      "description": [
        {
          "lang": "en",
          "value": "CWE-1287"
        }
      ]
    },
    {
      "type": "Secondary",
      "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
      "description": [
        {
          "lang": "en",
          "value": "CWE-1289"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Impact:\n\nFastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped.\n\nThis is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442\n\nPatches:\n\nUpgrade to fastify v5.8.5 or later.\n\nWorkarounds:\n\nNone. Upgrade to the patched version."
    }
  ],
  "lastModified": "2026-07-15T02:20:15.760",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:fastify:fastify:*:*:*:*:*:node.js:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F05DA184-C206-4A06-A5BA-97FBB69A274F",
              "versionEndExcluding": "5.8.5",
              "versionStartIncluding": "5.3.2"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb"
}