CVE-2026-115892

Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type

Medium 5.7

Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.

Assigner
GitHub_M
Published
2026-10-23
Updated
2026-10-23
Reserved
2026-10-23

Seen in other sources

Scores

SourceCVSSScoreSeverityVector
GitHub_M4.05.7MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Weaknesses

Affected

VendorProductVersions
bytecodealliance wasmtime >= 46.0.0, < 48.0.7 (affected)
>= 49.0.0, < 49.0.4 (affected)

References

Full CVE JSON record (5.2)

API · GitHub · cve.org

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "wasmtime",
          "vendor": "bytecodealliance",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 46.0.0, \u003c 48.0.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 49.0.0, \u003c 49.0.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 5.7,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "HIGH",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-843",
              "description": "CWE-843: Access of Resource Using Incompatible Type (\u0027Type Confusion\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-248",
              "description": "CWE-248: Uncaught Exception",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-23T21:26:54.528Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9pvw-hwfg-92h5",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9pvw-hwfg-92h5"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/pull/14819",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/pull/14819"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/pull/14820",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/pull/14820"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/pull/14827",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/pull/14827"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/commit/222ff3a65dab9aa7011f8c246937751a0bac5abd",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/commit/222ff3a65dab9aa7011f8c246937751a0bac5abd"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/commit/48dacc76241f06088e79f3ce1b17642f2f7bf158",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/commit/48dacc76241f06088e79f3ce1b17642f2f7bf158"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/commit/994549891c8a706cb4f2809f9d17b9f67b31e618",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/commit/994549891c8a706cb4f2809f9d17b9f67b31e618"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/releases/tag/v48.0.7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v48.0.7"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/releases/tag/v49.0.4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v49.0.4"
        }
      ],
      "source": {
        "advisory": "GHSA-9pvw-hwfg-92h5",
        "discovery": "UNKNOWN"
      },
      "title": "Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-115892",
    "datePublished": "2026-10-23T21:26:54.528Z",
    "dateReserved": "2026-10-23T19:37:27.176Z",
    "dateUpdated": "2026-10-23T21:26:54.528Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}