HTTP response splitting and DoS in i18next-http-middleware via unsanitised Content-Language header_CVE-2026-41683

{
    "lastseen": "",
    "description": "i18next-http-middleware is a middleware to be used with Node.js web frameworks like express or Fastify and also for Deno. Prior to version 3.9.3, i18next-http-middleware wrote user-controlled language values into the Content-Language response header after passing them through utils.escape(), which is an HTML-entity encoder that does not strip carriage return, line feed, or other control characters. When the application used an older i18next (< 19.5.0) that still exercised the backward-compatibility fallback at LanguageDetector.js:100 or otherwise produced a raw detected value, CRLF sequences in the attacker-controlled lng parameter reached res.setHeader('Content-Language', ...) verbatim. This issue has been patched in version 3.9.3.",
    "published": "2026-05-08T15:27:05.036Z",
    "modified": "2026-05-08T15:27:05.036Z",
    "type": "cve",
    "title": "HTTP response splitting and DoS in i18next-http-middleware via unsanitised Content-Language header",
    "source": "GitHub_M",
    "references": "https://github.com/i18next/i18next-http-middleware/security/advisories/GHSA-c3h8-g69v-pjrg",
    "id": "CVE-2026-41683",
    "bulletinFamily": "",
    "cwe": [
        "CWE-79",
        "CWE-113"
    ],
    "cvelist": null,
    "sourceData": "i18next i18next-http-middleware < 3.9.3",
    "sourceHref": "",
    "cvss": {
        "score": 8.6,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L",
        "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": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "i18next-http-middleware",
    "version": "< 3.9.3",
    "vendor": "i18next",
    "ai_description": "HTTP response splitting and DoS vulnerability in i18next-http-middleware via unsanitised Content-Language header",
    "ai_severity": "High",
    "ai_vendor": "i18next",
    "ai_product": "i18next-http-middleware",
    "ai_version": "< 3.9.3",
    "ai_score": 8.6
}