Out-of-bounds Write Affecting wasmtime package, versions >=32.0.0 <36.0.7>=37.0.0 <42.0.2>=43.0.0 <43.0.1


Severity

Recommended
0.0
critical
0
10

CVSS assessment by Snyk's Security Team. Learn more

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Out-of-bounds Write vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-RUST-WASMTIME-15967399
  • published10 Apr 2026
  • disclosed9 Apr 2026
  • creditShun Kashiwa

Introduced: 9 Apr 2026

NewCVE-2026-34971  (opens in a new tab)
CWE-125  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade wasmtime to version 36.0.7, 42.0.2, 43.0.1 or higher.

Overview

Affected versions of this package are vulnerable to Out-of-bounds Write in the heap access on aarch64 Cranelift. An attacker can gain unauthorized access to host system memory by exploiting a miscompilation bug, allowing arbitrary read and write operations outside the intended memory bounds. This is only exploitable if Spectre mitigations are disabled on aarch64 systems.

CVSS Base Scores

version 4.0
version 3.1