CVE-2026-27204CWE-400CWE-770CWE-774CWE-789

Wasmtime WASI implementations are vulnerable to guest-controlled resource exhaustion

Medium · published February 24, 2026

CVSS v4.0
6.9
EPSS
0%
Percentile
27.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
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
EPSS
0.00345 · 27.4th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-770 · Allocation of Resources Without Limits or Throttling; CWE-774 · Allocation of File Descriptors or Handles Without Limits or Throttling; CWE-789 · Memory Allocation with Excessive Size Value
Published
2026-02-24T21:23Z
EPSS history
Timeline
  • 24 FEB 21:23Z
    Wasmtime WASI implementations are vulnerable to guest-controlled resource exhaustion
    cvelistv5