CVE-2026-27204 MEDIUM

CVE-2026-27204: Wasmtime WASI implementations are vulnerable to guest-controlled resource exhaustion

Vendor Bytecodealliance
Product wasmtime
Weakness CWE-400
Published February 24, 2026
Last update February 27, 2026

CVSS base score

6.9/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

What the vulnerability does

01Description

Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of WASI host interfaces are susceptible to guest-controlled resource exhaustion on the host. Wasmtime did not appropriately place limits on resource allocations requested by the guests. This serves as a Denial of Service vector. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 have all been released with the fix for this issue. These versions do not prevent this issue in their default configuration to avoid breaking preexisting behaviors. All versions of Wasmtime have appropriate knobs to prevent this behavior, and Wasmtime 42.0.0-and-later will have these knobs tuned by default to prevent this issue from happening. There are no known workarounds for this issue without upgrading. Embedders are recommended to upgrade and configure their embeddings as necessary to prevent possibly-malicious guests from triggering this issue.

Key dates

02Disclosure timeline

February 24, 2026 CVE published
February 27, 2026 Record updated