Fastify’s Content-Type header tab character allows body validation bypass_CVE-2026-25223

{
    "lastseen": "",
    "description": "Fastify is a fast and low overhead web framework, for Node.js. Prior to version 5.7.2, a validation bypass vulnerability exists in Fastify where request body validation schemas specified by Content-Type can be completely circumvented. By appending a tab character (\\t) followed by arbitrary content to the Content-Type header, attackers can bypass body validation while the server still processes the body as the original content type. This issue has been patched in version 5.7.2.",
    "published": "2026-02-03T21:21:40.268Z",
    "modified": "2026-02-03T21:21:40.268Z",
    "type": "cve",
    "title": "Fastify's Content-Type header tab character allows body validation bypass",
    "source": "GitHub_M",
    "references": "https://github.com/fastify/fastify/security/advisories/GHSA-jx2c-rxcm-jvmq\nhttps://github.com/fastify/fastify/commit/32d7b6add39ddf082d92579a58bea7018c5ac821\nhttps://hackerone.com/reports/3464114\nhttps://fastify.dev/docs/latest/Reference/Validation-and-Serialization\nhttps://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/content-type-parser.js#L125\nhttps://github.com/fastify/fastify/blob/759e9787b5669abf953068e42a17bffba7521348/lib/validation.js#L272",
    "id": "CVE-2026-25223",
    "bulletinFamily": "",
    "cwe": [
        "CWE-436"
    ],
    "cvelist": null,
    "sourceData": "fastify fastify < 5.7.2",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "fastify",
    "version": "< 5.7.2",
    "vendor": "fastify",
    "ai_description": "",
    "ai_severity": "",
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    "ai_product": "",
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    "ai_score": 0
}