VulnerabilityDeferred

CVE-2026-115892

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.

MEDIUM 5.7EPSS 0.43%

Does this matter?

Lower severity and a low EPSS score (0.43%). Track it; it rarely justifies an emergency change on its own.

Description

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 4.0: 5.7 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/M
EPSS: 0.43% probability · 37th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-248, CWE-843
Source: security-advisories@github.com

EPSS trend

EPSS moved from 0.6% on 24 October 2026 to 0.4% on 26 October 2026.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.