Hono: Cookie helper does not sanitize sameSite and priority, allowing Set-Cookie injection_CVE-2026-47675

{
    "lastseen": "",
    "description": "Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \\r, \\n), but does not apply the same validation to sameSite and priority. An application that passes user-controlled input into either option may produce a Set-Cookie response header containing attacker-chosen additional attributes. This vulnerability is fixed in 4.12.21.",
    "published": "2026-05-28T15:28:23.458Z",
    "modified": "2026-05-28T15:28:23.458Z",
    "type": "cve",
    "title": "Hono: Cookie helper does not sanitize sameSite and priority, allowing Set-Cookie injection",
    "source": "GitHub_M",
    "references": "https://github.com/honojs/hono/security/advisories/GHSA-3hrh-pfw6-9m5x",
    "id": "CVE-2026-47675",
    "bulletinFamily": "",
    "cwe": [
        "CWE-113",
        "CWE-1287"
    ],
    "cvelist": null,
    "sourceData": "honojs hono < 4.12.21",
    "sourceHref": "",
    "cvss": {
        "score": 4.3,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
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            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "hono",
    "version": "< 4.12.21",
    "vendor": "honojs",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}