FKIE_CVE-2026-35041

Vulnerability from fkie_nvd - Published: 2026-04-09 16:16 - Updated: 2026-04-14 20:15
Severity ?
4.2 (Medium) - CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
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.
References
security-advisories@github.comhttps://github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94Patch
security-advisories@github.comhttps://github.com/nearform/fast-jwt/pull/595Issue Tracking, Patch
security-advisories@github.comhttps://github.com/nearform/fast-jwt/releases/tag/v6.2.1Product, Release Notes
security-advisories@github.comhttps://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxfExploit, Mitigation, Vendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxfExploit, Mitigation, Vendor Advisory
Impacted products
Vendor Product Version
nearform fast-jwt *
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "0E23134A-F7C0-40FB-AB4C-5B056C011E0B",
              "versionEndExcluding": "6.2.1",
              "versionStartIncluding": "5.0.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "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."
    }
  ],
  "id": "CVE-2026-35041",
  "lastModified": "2026-04-14T20:15:13.637",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 4.2,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "HIGH",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 0.5,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-04-09T16:16:27.383",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
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        "Patch"
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      "url": "https://github.com/nearform/fast-jwt/pull/595"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
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        "Release Notes"
      ],
      "url": "https://github.com/nearform/fast-jwt/releases/tag/v6.2.1"
    },
    {
      "source": "security-advisories@github.com",
      "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"
      ],
      "url": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-1333"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}


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