CVE-2026-34946

{
  "id": "CVE-2026-34946",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-09T19:16:24.490",
  "lastModified": "2026-10-26T22:10:00.163",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch compiler contains a vulnerability where the compilation of the table.fill instruction can result in a host panic. This means that a valid guest can be compiled with Winch, on any architecture, and cause the host to panic. This represents a denial-of-service vulnerability in Wasmtime due to guests being able to trigger a panic. The specific issue is that a historical refactoring changed how compiled code referenced tables within the table.* instructions. This refactoring forgot to update the Winch code paths associated as well, meaning that Winch was using the wrong indexing scheme. Due to the feature support of Winch the only problem that can result is tables being mixed up or nonexistent tables being used, meaning that the guest is limited to panicking the host (using a nonexistent table), or executing spec-incorrect behavior and modifying the wrong table. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1."
    },
    {
      "lang": "es",
      "value": "Wasmtime es un entorno de ejecución para WebAssembly. Desde la versión 25.0.0 hasta antes de las versiones 36.0.7, 42.0.2 y 43.0.1, el compilador Winch de Wasmtime contiene una vulnerabilidad donde la compilación de la instrucción table.fill puede resultar en un pánico del host. Esto significa que un invitado válido puede ser compilado con Winch, en cualquier arquitectura, y causar que el host entre en pánico. Esto representa una vulnerabilidad de denegación de servicio en Wasmtime debido a que los invitados pueden desencadenar un pánico. El problema específico es que una refactorización histórica cambió la forma en que el código compilado referenciaba tablas dentro de las instrucciones table.*. Esta refactorización olvidó actualizar también las rutas de código de Winch asociadas, lo que significa que Winch estaba utilizando el esquema de indexación incorrecto. Debido al soporte de características de Winch, el único problema que puede resultar es que las tablas se mezclen o que se utilicen tablas inexistentes, lo que significa que el invitado se limita a provocar el pánico del host (utilizando una tabla inexistente), o a ejecutar un comportamiento incorrecto según la especificación y modificar la tabla equivocada. Esta vulnerabilidad está corregida en las versiones 36.0.7, 42.0.2 y 43.0.1."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "bytecodealliance",
          "product": "wasmtime",
          "versions": [
            {
              "version": ">= 25.0.0, < 36.0.7",
              "status": "affected"
            },
            {
              "version": ">= 37.0.0, < 42.0.2",
              "status": "affected"
            },
            {
              "version": ">= 43.0.0, < 44.0.1",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
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        "source": "[email protected]",
        "type": "Secondary",
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          "confidentialityRequirement": "NOT_DEFINED",
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        "ssvcData": {
          "timestamp": "2026-04-09T19:33:22.517926Z",
          "id": "CVE-2026-34946",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
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            {
              "technicalImpact": "partial"
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          "role": "CISA Coordinator",
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  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-670"
        }
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  "references": [
    {
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q49f-xg75-m9xw",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}