Use After Free Affecting wasmtime package, versions >=0.37.0 <0.38.2



    Attack Complexity High
    Confidentiality High
Expand this section
8.8 high

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  • Snyk ID SNYK-RUST-WASMTIME-2957524
  • published 21 Jul 2022
  • disclosed 20 Jul 2022
  • credit Alex Crichton, Nick Fitzgerald, Jamey Sharp

How to fix?

Upgrade wasmtime to version 0.38.2 or higher.


Affected versions of this package are vulnerable to Use After Free in the runtime garbage collector. When a host passes non-null externrefs to WebAssembly, garbage collection is triggered, while active Wasm frames remain on the stack. Live references from these frames can be reclaimed and reallocated.

Note: This vulnerability can be worked around by passing false to wasmtime::Config::wasm_reference_types.