CVE-2022-31146: Wasmtime is a standalone runtime for WebAssembly. There is a bug in the Wasmtime's code generator, Cranelift, where functions using reference types ma...

Description

Wasmtime is a standalone runtime for WebAssembly. There is a bug in the Wasmtime's code generator, Cranelift, where functions using reference types may be incorrectly missing metadata required for runtime garbage collection. This means that if a GC happens at runtime then the GC pass will mistakenly think these functions do not have live references to GC'd values, reclaiming them and deallocating them. The function will then subsequently continue to use the values assuming they had not been GC'd, leading later to a use-after-free. This bug was introduced in the migration to the `regalloc2` register allocator that occurred in the Wasmtime 0.37.0 release on 2022-05-20. This bug has been patched and users should upgrade to Wasmtime version 0.38.2. Mitigations for this issue can be achieved by disabling the reference types proposal by passing `false` to `wasmtime::Config::wasm_reference_types` or downgrading to Wasmtime 0.36.0 or prior.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.86%

53.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-416

Affected Software

Vendor	Product	Versions
Bytecodealliance	Cranelift-Codegen	>= 0.84.0, < 0.85.2
Bytecodealliance	Wasmtime	>= 0.37.0, < 0.38.2

References

https://github.com/WebAssembly/reference-typesThird Party Advisory
https://github.com/bytecodealliance/wasmtime/Product, Third Party Advisory
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-5fhj-g3p3-pq9gMitigation, Third Party Advisory
https://github.com/WebAssembly/reference-typesThird Party Advisory
https://github.com/bytecodealliance/wasmtime/Product, Third Party Advisory
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-5fhj-g3p3-pq9gMitigation, Third Party Advisory

Timeline

Published: Jul 21, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-31146?

Wasmtime is a standalone runtime for WebAssembly. There is a bug in the Wasmtime's code generator, Cranelift, where functions using reference types may be incorrectly missing metadata required for runtime garbage collection. This means that if a GC happens at runtime then the GC pass will mistakenly think these functions do not have live references to GC'd values, reclaiming them and deallocating them. The function will then subsequently continue to use the values assuming they had not been GC'd, leading later to a use-after-free. This bug was introduced in the migration to the `regalloc2` register allocator that occurred in the Wasmtime 0.37.0 release on 2022-05-20. This bug has been patched and users should upgrade to Wasmtime version 0.38.2. Mitigations for this issue can be achieved by disabling the reference types proposal by passing `false` to `wasmtime::Config::wasm_reference_types` or downgrading to Wasmtime 0.36.0 or prior.

How severe is CVE-2022-31146?

CVE-2022-31146 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.86% probability of exploitation in the next 30 days.

How do I fix CVE-2022-31146?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.