ReDoS in fast-jwt when using RegExp in allowed* leading to CPU exhaustion during token verification_CVE-2026-35041

{
    "lastseen": "",
    "description": "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.",
    "published": "2026-04-09T14:55:22.807Z",
    "modified": "2026-04-09T16:15:25.352Z",
    "type": "cve",
    "title": "ReDoS in fast-jwt when using RegExp in allowed* leading to CPU exhaustion during token verification",
    "source": "GitHub_M",
    "references": "https://github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf\nhttps://github.com/nearform/fast-jwt/pull/595\nhttps://github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94\nhttps://github.com/nearform/fast-jwt/releases/tag/v6.2.1",
    "id": "CVE-2026-35041",
    "bulletinFamily": "",
    "cwe": [
        "CWE-1333"
    ],
    "cvelist": null,
    "sourceData": "nearform fast-jwt >= 5.0.0, < 6.2.1",
    "sourceHref": "",
    "cvss": {
        "score": 4.2,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "fast-jwt",
    "version": ">= 5.0.0, < 6.2.1",
    "vendor": "nearform",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}