{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:bytecodealliance:wasmtime:43.0.0:*:*:*:*:rust:*:*",
            "extracted_events": [
              {
                "introduced": "43.0.0"
              },
              {
                "fixed": "43.0.1"
              },
              {
                "last_affected": "43.0.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_STRING"
            ]
          },
          "events": [
            {
              "introduced": "be23469ece57c0be64904f12111c8d808b0ce4ac"
            },
            {
              "fixed": "cd4b6ed9b2a59cd3f317bff812126dd6a0e92dd2"
            }
          ],
          "repo": "https://github.com/bytecodealliance/wasmtime",
          "type": "GIT"
        }
      ],
      "versions": [
        "43.0.0"
      ]
    }
  ],
  "aliases": [
    "GHSA-hfr4-7c6c-48w2"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-416"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34983.json"
  },
  "details": "Wasmtime is a runtime for WebAssembly. In 43.0.0, cloning a wasmtime::Linker is unsound and can result in use-after-free bugs. This bug is not controllable by guest Wasm programs. It can only be triggered by a specific sequence of embedder API calls made by the host. Specifically, the following steps must occur to trigger the bug clone a wasmtime::Linker, drop the original linker instance, use the new, cloned linker instance, resulting in a use-after-free. This vulnerability is fixed in 43.0.1.",
  "id": "CVE-2026-34983",
  "modified": "2026-07-08T05:36:40.016821256Z",
  "published": "2026-04-09T18:47:26.575Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34983.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34983"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:4.0/AV:P/AC:H/AT:P/PR:H/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`"
}