jsonwebtoken has Type Confusion that leads to potential authorization bypass_CVE-2026-25537

{
    "lastseen": "",
    "description": "jsonwebtoken is a JWT lib in rust. Prior to version 10.3.0, there is a Type Confusion vulnerability in jsonwebtoken, specifically, in its claim validation logic. When a standard claim (such as nbf or exp) is provided with an incorrect JSON type (Like a String instead of a Number), the library\u2019s internal parsing mechanism marks the claim as \u201cFailedToParse\u201d. Crucially, the validation logic treats this \u201cFailedToParse\u201d state identically to \u201cNotPresent\u201d. This means that if a check is enabled (like: validate_nbf = true), but the claim is not explicitly marked as required in required_spec_claims, the library will skip the validation check entirely for the malformed claim, treating it as if it were not there. This allows attackers to bypass critical time-based security restrictions (like \u201cNot Before\u201d checks) and commit potential authentication and authorization bypasses. This issue has been patched in version 10.3.0.",
    "published": "2026-02-04T21:31:53.511Z",
    "modified": "2026-02-04T21:31:53.511Z",
    "type": "cve",
    "title": "jsonwebtoken has Type Confusion that leads to potential authorization bypass",
    "source": "GitHub_M",
    "references": "https://github.com/Keats/jsonwebtoken/security/advisories/GHSA-h395-gr6q-cpjc\nhttps://github.com/Keats/jsonwebtoken/commit/abbc3076742c4161347bc6b8bf4aa5eb86e1dc01",
    "id": "CVE-2026-25537",
    "bulletinFamily": "",
    "cwe": [
        "CWE-843"
    ],
    "cvelist": null,
    "sourceData": "Keats jsonwebtoken < 10.3.0",
    "sourceHref": "",
    "cvss": {
        "score": 5.5,
        "severity": "MEDIUM",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P",
        "version": "4.0"
    },
    "cvss2": [],
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        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
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            "baseScore": 0,
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "jsonwebtoken",
    "version": "< 10.3.0",
    "vendor": "Keats",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}