{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "24.0.7"
              },
              {
                "introduced": "25.0.0"
              },
              {
                "fixed": "36.0.7"
              },
              {
                "introduced": "37.0.0"
              },
              {
                "fixed": "42.0.2"
              },
              {
                "introduced": "43.0.0"
              },
              {
                "fixed": "43.0.1"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "a15daff0bfc965d1656ddcf9beaa1d085c3a7410"
            },
            {
              "introduced": "0b195ef5db76c02fb5392ec1418c58bdc5537d41"
            },
            {
              "fixed": "09539085b9b514b65d5c51e2905dc38f6eb414b9"
            },
            {
              "introduced": "7b3d6ae79e9153a2477668062f5622c10333925f"
            },
            {
              "fixed": "403f9929d4e13ed87c76471d4f4bc8d381c876eb"
            },
            {
              "introduced": "be23469ece57c0be64904f12111c8d808b0ce4ac"
            },
            {
              "fixed": "cd4b6ed9b2a59cd3f317bff812126dd6a0e92dd2"
            }
          ],
          "repo": "https://github.com/bytecodealliance/wasmtime",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-jxhv-7h78-9775"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-129"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34942.json"
  },
  "details": "Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings improperly verified the alignment of reallocated strings. This meant that unaligned pointers could be passed to the host for transcoding which would trigger a host panic. This panic is possible to trigger from malicious guests which transfer very specific strings across components with specific addresses. Host panics are considered a DoS vector in Wasmtime as the panic conditions are controlled by the guest in this situation. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.",
  "id": "CVE-2026-34942",
  "modified": "2026-07-15T01:49:07.703868927Z",
  "published": "2026-04-09T18:32:56.456Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34942.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxhv-7h78-9775"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34942"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Wasmtime panics when transcoding misaligned utf-16 strings"
}