{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "last_affected": "6.1.0"
              },
              {
                "fixed": "6.2.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_RANGE"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "e07b1fd23f02a47f1be677a21a4f07607b478e66"
            }
          ],
          "repo": "https://github.com/nearform/fast-jwt",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-hm7r-c7qw-ghp6"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-345",
      "CWE-636"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/35xxx/CVE-2026-35042.json"
  },
  "details": "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.",
  "id": "CVE-2026-35042",
  "modified": "2026-07-08T05:37:27.326831469Z",
  "published": "2026-04-06T17:02:12.180Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/35xxx/CVE-2026-35042.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35042"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "fast-jwt accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)"
}