{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0"
                  },
                  {
                    "fixed": "36.0.20"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              },
              {
                "range": [
                  {
                    "introduced": "37.0.0"
                  },
                  {
                    "fixed": "48.0.8"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              },
              {
                "range": [
                  {
                    "introduced": "49.0.0"
                  },
                  {
                    "fixed": "49.0.5"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              },
              {
                "range": [
                  {
                    "introduced": "50.0.0"
                  },
                  {
                    "fixed": "50.0.1"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "b265f78b1e92e12240ec7bdc21c7a559d2df968e"
            },
            {
              "introduced": "7b3d6ae79e9153a2477668062f5622c10333925f"
            },
            {
              "fixed": "7b6c29ec3e9a49c97da231665cbd8eead9ccbda0"
            },
            {
              "introduced": "17830bd3c0331d920a8aa38846eebc4d46d98c23"
            },
            {
              "fixed": "805a0f15320e8836cf2b9f001b53d884bf866c89"
            },
            {
              "introduced": "ebe5e8df1f4e12c5fc2f5954926881d8d61367d8"
            },
            {
              "fixed": "c307ec81de02852d815e9849f7c89d955c03c30d"
            }
          ],
          "repo": "https://github.com/bytecodealliance/wasmtime",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-h4wp-g4x3-7398"
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-444"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126406.json"
  },
  "details": "The wasmtime-wasi-http p2 implementation in Wasmtime before 36.0.20, 37.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 can send conflicting content-length headers, or ones not matching the body, in outgoing requests. A guest that reuses a received response's headers resource to send a bodyless request can enable request smuggling against non-compliant servers, potentially bypassing embedder destination access controls.",
  "id": "CVE-2026-126406",
  "modified": "2026-11-15T02:31:04.340626894Z",
  "published": "2026-11-13T09:35:44.314Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126406.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-h4wp-g4x3-7398"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126406"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/wasmtime-before-36.0.20-http-request-smuggling-via-wasi-http-p2-content-length"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Wasmtime before 36.0.20 HTTP Request Smuggling via wasi-http p2 Content-Length"
}