FKIE_CVE-2026-35042

Vulnerability from fkie_nvd - Published: 2026-04-06 17:17 - Updated: 2026-06-17 10:40
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that fast-jwt does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC.
References
security-advisories@github.comhttps://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6Exploit, Mitigation, Vendor Advisory
security-advisories@github.comhttps://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11Technical Description
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6Exploit, Mitigation, Vendor Advisory
Impacted products
Vendor Product Version
nearform fast-jwt *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "fast-jwt",
          "vendor": "nearform",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c= 6.1.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "FD2BA255-333A-4CF2-9B8E-C685DF7A11A9",
              "versionEndExcluding": "6.2.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 \u00a74.1.11. When a JWS token contains a crit array listing extensions that fast-jwt does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC."
    }
  ],
  "id": "CVE-2026-35042",
  "lastModified": "2026-06-17T10:40:00.837",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-35042",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-04-07T15:19:36.239438Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-04-06T17:17:13.410",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Technical Description"
      ],
      "url": "https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-345"
        },
        {
          "lang": "en",
          "value": "CWE-636"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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