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
GitHub_M
Published
2026-10-23
2026-10-23
Updated
2026-10-23
2026-10-23
Reserved
2026-10-23
2026-10-23
Seen in other sources
- OSV.dev RUSTSEC-2026-0378
2026-10-19 ·
4 days before publication
Panic lowering a host-created component model stream into a guest that expects a different payload type - GitHub advisory GHSA-9pvw-hwfg-92h5
2026-10-23 ·
same day as publication
Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type
Scores
| Source | CVSS | Score | Severity | Vector |
|---|---|---|---|---|
| GitHub_M | 4.0 | 5.7 | Medium | 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 |
Weaknesses
Affected
| Vendor | Product | Versions |
|---|---|---|
| bytecodealliance | wasmtime | >= 46.0.0, < 48.0.7 (affected) >= 49.0.0, < 49.0.4 (affected) |
References
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9pvw-hwfg-92h5 x_refsource_CONFIRM
- https://github.com/bytecodealliance/wasmtime/pull/14819 x_refsource_MISC
- https://github.com/bytecodealliance/wasmtime/pull/14820 x_refsource_MISC
- https://github.com/bytecodealliance/wasmtime/pull/14827 x_refsource_MISC
- https://github.com/bytecodealliance/wasmtime/commit/222ff3a65dab9aa7011f8c246937751a0bac5abd x_refsource_MISC
- https://github.com/bytecodealliance/wasmtime/commit/48dacc76241f06088e79f3ce1b17642f2f7bf158 x_refsource_MISC
- https://github.com/bytecodealliance/wasmtime/commit/994549891c8a706cb4f2809f9d17b9f67b31e618 x_refsource_MISC
- https://github.com/bytecodealliance/wasmtime/releases/tag/v48.0.7 x_refsource_MISC
- https://github.com/bytecodealliance/wasmtime/releases/tag/v49.0.4 x_refsource_MISC
Full CVE JSON record (5.2)
{
"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"
}