JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass_CVE-2026-22817

{
    "lastseen": "",
    "description": "Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.11.4, there is a flaw in Hono\u2019s JWK/JWKS JWT verification middleware allowed the JWT header\u2019s alg value to influence signature verification when the selected JWK did not explicitly specify an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted. As part of this fix, the JWT middleware now requires the alg option to be explicitly specified. This prevents algorithm confusion by ensuring that the verification algorithm is not derived from untrusted JWT header values. This vulnerability is fixed in 4.11.4.",
    "published": "2026-01-13T19:49:55.316Z",
    "modified": "2026-01-13T19:49:55.316Z",
    "type": "cve",
    "title": "JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass",
    "source": "GitHub_M",
    "references": "https://github.com/honojs/hono/security/advisories/GHSA-f67f-6cw9-8mq4\nhttps://github.com/honojs/hono/commit/cc0aa7ae327ed84cc391d29086dec2a3e44e7a1f",
    "id": "CVE-2026-22817",
    "bulletinFamily": "",
    "cwe": [
        "CWE-347"
    ],
    "cvelist": null,
    "sourceData": "honojs hono < 4.11.4",
    "sourceHref": "",
    "cvss": {
        "score": 8.2,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N",
        "version": "3.1"
    },
    "cvss2": [],
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        "confidentialityImpact": "",
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        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "hono",
    "version": "< 4.11.4",
    "vendor": "honojs",
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}