{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.23.35"
              },
              {
                "introduced": "1.0.0-M1"
              },
              {
                "fixed": "1.0.0-M47"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "756ce63aee681c5b632bbeafe0b8fde2f3d237f4"
            },
            {
              "fixed": "a83f5f4f7e14c5b4d4a91dd71b105cbbbb391298"
            },
            {
              "fixed": "6083780a3009bd7b26033b0ceb3d32c658b0377e"
            },
            {
              "fixed": "9feaf8677951a52af906ae9664ff6f0543d9d810"
            }
          ],
          "repo": "https://github.com/http4s/http4s",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-8h4c-x2wg-6xp8"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-444"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/69xxx/CVE-2026-69204.json"
  },
  "details": "Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/1.1 does not reject messages containing both Transfer-Encoding and Content-Length, so an intermediary and Ember can select different body framing rules. When ember-server is behind a keep-alive intermediary that forwards both headers and frames by Content-Length, an unauthenticated attacker can smuggle a second request, bypass intermediary access controls, poison caches, or cause a victim request to be joined to an attacker-controlled prefix. The shared response parser can also desynchronize an ember-client connection when a malicious or compromised upstream sends both headers. This issue is fixed in versions 0.23.35 and 1.0.0-M47.",
  "id": "CVE-2026-69204",
  "modified": "2026-09-18T03:30:24.725198766Z",
  "published": "2026-09-15T18:43:14.850Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/http4s/http4s/releases/tag/v0.23.35"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/http4s/releases/tag/v1.0.0-M47"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/69xxx/CVE-2026-69204.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/http4s/http4s/security/advisories/GHSA-8h4c-x2wg-6xp8"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-69204"
    },
    {
      "type": "FIX",
      "url": "https://github.com/http4s/http4s/commit/9feaf8677951a52af906ae9664ff6f0543d9d810"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Http4s: Ember accepts Transfer-Encoding combined with Content-Length (CL.TE request smuggling)"
}