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CVE-2026-115892

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

Published
2026-10-23
Last modified
2026-10-23
CNA
GitHub_M
NVD status
Deferred
CWE
CWE-248 CWE-843

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CVSS v3.1 (listed by NVD)
—
Not scored
CVSS v4.0 (listed by NVD)
5.7
MEDIUM
Scored by github.com (not yet scored by NVD)
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS (listed by CVE.org)
5.7
MEDIUM
Scored by CNA (GitHub_M) · v4.0
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
EPSS exploit probability
0.6%
Percentile 46.2%
as of 2026-10-24
CISA KEV
—
Not listed

Attack conditions and impact

Derived from the CNA (via NVD) CVSS 4.0 vector
NetworkAdminUser actionConditions Confidentiality NIntegrity NAvailability H
MetricValueMeaning
Attack vector AVNNetwork
Attack complexity ACHHigh (conditions required)
Attack requirements ATPPresent
Privileges required PRHAdministrator
User interaction UIPPassive
Confidentiality (vulnerable system) VCNNone
Integrity (vulnerable system) VINNone
Availability (vulnerable system) VAHHigh
Confidentiality (subsequent systems) SCNNone
Integrity (subsequent systems) SINNone
Availability (subsequent systems) SANNone
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Description

NVD

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.

CVSS assessments

ProviderVersionScoreVector
NVD / [email protected] (Secondary)4.05.7 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA / GitHub_M4.05.7 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Affected products and packages

CNA (CVE.org)

VendorProductVersions
bytecodealliancewasmtime
affected: >= 46.0.0, < 48.0.7
affected: >= 49.0.0, < 49.0.4

Open-source packages (GitHub Advisory / OSV)

GHSA-9pvw-hwfg-92h5 GHSA MEDIUM reviewed

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

EcosystemPackageAffected versionsFixed in
crates.iowasmtime>= 46.0.0, < 48.0.748.0.7
crates.iowasmtime>= 49.0.0, < 49.0.449.0.4
RUSTSEC-2026-0378 OSV

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

EcosystemPackageAffected versionsFixed in
crates.iowasmtime>= 46.0.0, < 48.0.7; >= 49.0.0, < 49.0.448.0.7, 49.0.4

Linux distribution status

Red Hat ↗ moderate

ReleasePackageStatusFixed version / notes
Red Hat Connectivity Link 1rhcl-1/wasm-shim-rhel9fix deferred
Red Hat Enterprise Linux 10tree-sitterfix deferred
Red Hat Enterprise Linux 10virt-firmware-rsfix deferred

Debian ↗

ReleasePackageStatusFixed version / notes
forkyrust-wasmtimenot-affected unimportant
sidrust-wasmtimenot-affected unimportant
trixierust-wasmtimenot-affected unimportant

Ubuntu ↗ Fetching

References (12)