CVE-2022-31104 — Wasmtime is a standalone runtime for WebAssembly

Wasmtime is a standalone runtime for WebAssembly. In affected versions wasmtime's implementation of the SIMD proposal for WebAssembly on x86_64 contained two distinct bugs in the instruction lowerings implemented in Cranelift. The aarch64 implementation of the simd proposal

01What is this vulnerability?

Wasmtime is a standalone runtime for WebAssembly. In affected versions wasmtime's implementation of the SIMD proposal for WebAssembly on x86_64 contained two distinct bugs in the instruction lowerings implemented in Cranelift. The aarch64 implementation of the simd proposal is not affected. The bugs were presented in the `i8x16.swizzle` and `select` WebAssembly instructions. The `select`…

02Affected products

Vendor	Product	Versions
bytecodealliance	wasmtime	wasmtime: < 0.38.1, cranelift-codegen: < 0.85.0

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2022-06-27T23:20:13.000Z
• Last modified: 2025-04-23T18:06:10.136Z

09References

• github.com — https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jqwc-c49r-…
• github.com — https://github.com/bytecodealliance/wasmtime/pull/4317
• github.com — https://github.com/bytecodealliance/wasmtime/pull/4318
• docs.rs — https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.wasm_simd
• github.com — https://github.com/webassembly/simd
• webassembly.github.io — https://webassembly.github.io/spec/