CVE-2026-35041

{
  "id": "CVE-2026-35041",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-09T16:16:27.383",
  "lastModified": "2026-10-26T22:10:00.163",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "fast-jwt provides fast JSON Web Token (JWT) implementation. From 5.0.0 to 6.2.0, a denial-of-service condition exists in fast-jwt when the allowedAud verification option is configured using a regular expression. Because the aud claim is attacker-controlled and the library evaluates it against the supplied RegExp, a crafted JWT can trigger catastrophic backtracking in the JavaScript regex engine, resulting in significant CPU consumption during verification. This vulnerability is fixed in 6.2.1."
    },
    {
      "lang": "es",
      "value": "fast-jwt proporciona una implementación rápida de JSON Web Token (JWT). Desde la versión 5.0.0 hasta la 6.2.0, existe una condición de denegación de servicio en fast-jwt cuando la opción de verificación allowedAud se configura utilizando una expresión regular. Debido a que la declaración aud está controlada por el atacante y la biblioteca la evalúa contra la RegExp proporcionada, un JWT manipulado puede desencadenar un retroceso catastrófico en el motor de expresiones regulares de JavaScript, lo que resulta en un consumo significativo de CPU durante la verificación. Esta vulnerabilidad se corrige en la versión 6.2.1."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "nearform",
          "product": "fast-jwt",
          "versions": [
            {
              "version": ">= 5.0.0, < 6.2.1",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H",
          "baseScore": 4.2,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "HIGH",
          "userInteraction": "REQUIRED",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 0.5,
        "impactScore": 3.6
      },
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-09T16:14:14.434470Z",
          "id": "CVE-2026-35041",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-1333"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:node.js:*:*",
              "versionStartIncluding": "5.0.0",
              "versionEndExcluding": "6.2.1",
              "matchCriteriaId": "0E23134A-F7C0-40FB-AB4C-5B056C011E0B"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/nearform/fast-jwt/pull/595",
      "source": "[email protected]",
      "tags": [
        "Issue Tracking",
        "Patch"
      ]
    },
    {
      "url": "https://github.com/nearform/fast-jwt/releases/tag/v6.2.1",
      "source": "[email protected]",
      "tags": [
        "Product",
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf",
      "source": "[email protected]",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ]
    }
  ]
}