HTTP response splitting and DoS in i18next-http-middleware via unsanitised Content-Language header

{
  "id": "562570014787bb5c512703d70bc929ae8bb1ae823ad9835d9a0b116ab4b063e3",
  "url": "https://osv.dev/vulnerability/CVE-2026-41683",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "HTTP response splitting and DoS in i18next-http-middleware via unsanitised Content-Language header",
    "summary": "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.",
    "evidence": "osv:CVE-2026-41683",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-41683",
      "aliases": [
        "CVE-2026-41683",
        "GHSA-c3h8-g69v-pjrg"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/i18next/i18next-http-middleware",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c6624343818c63e9877ba98125f7451580eae618"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.9.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.9.3"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.9.2",
            "v3.9.1",
            "v3.9.0",
            "v3.8.3",
            "v3.8.2",
            "v3.8.1",
            "v3.8.0",
            "v3.7.4",
            "v3.7.3",
            "v3.7.2",
            "v3.7.1",
            "v3.7.0",
            "v3.6.0",
            "v3.5.0",
            "v3.4.1",
            "v3.4.0",
            "v3.3.2",
            "v3.3.1",
            "v3.3.0",
            "v3.2.2",
            "v3.2.1",
            "v3.2.0",
            "v3.1.6",
            "v3.1.5",
            "v3.1.4",
            "v3.1.3",
            "v3.1.2",
            "v3.1.1",
            "v3.1.0",
            "v3.0.6",
            "v3.0.5",
            "v3.0.4",
            "v3.0.3",
            "v3.0.2",
            "v3.0.1",
            "v3.0.0",
            "v2.1.2",
            "v2.1.1",
            "v2.1.0",
            "v2.0.0",
            "v1.3.1",
            "v1.3.0",
            "v1.2.1",
            "v1.2.0",
            "v1.1.0",
            "v1.0.7",
            "v1.0.6",
            "v1.0.5",
            "v1.0.4",
            "v1.0.3",
            "v1.0.2",
            "v1.0.1",
            "v1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-41683.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:41.991280463Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41683.json",
        "https://github.com/i18next/i18next-http-middleware/security/advisories/GHSA-c3h8-g69v-pjrg",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-41683"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-113",
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41683.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-41683",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 509423,
  "published_at": "2026-05-08T15:27:05.036+00:00"
}