Out-of-bounds Write Affecting wasmtime package, versions >=28.0.0 <36.0.7>=37.0.0 <42.0.2>=43.0.0 <43.0.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RUST-WASMTIME-15967235
- published10 Apr 2026
- disclosed9 Apr 2026
- creditShun Kashiwa
Introduced: 9 Apr 2026
NewCVE-2026-34987 (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 via incorrect memory offset handling in the Winch compiler backend. An attacker can execute arbitrary code, cause denial of service, or leak sensitive data by crafting a malicious WebAssembly module that accesses host memory outside its intended sandbox. This is only exploitable if the non-default Winch compiler backend is enabled.