Vulnerability GHSA-5fhj-g3p3-pq9g

Medium Risk
MEDIUM RISK
CVSS Score: 6.4
Score Range: 4.0–6.9
Medium severity vulnerabilities (CVSS 4.0–6.9). Important issues that meaningfully reduce security confidence.
4 years ago
July 20, 2022 at 10:47 PM UTC
Wasmtime vulnerable to Use After Free with `externref`s
0.84.0 - 0.85.1
0.84.0 - 0.85.1

Summary

Wasmtime vulnerable to Use After Free with `externref`s

Details

There is a bug in Wasmtime's code generator, Cranelift, where functions using reference types may be incorrectly missing metadata required for runtime garbage collection (GC). This means that if a GC happens at runtime then the collector will mistakenly think some Wasm stack frames do not have live references to garbage collected values and therefore reclaim and deallocate them. The function can then subsequently continue to use the values, leading later to use-after-free bugs. This bug was introduced in Cranelift's migration to the regalloc2 register allocator 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 doing one of:

Timeline

Published
4 years ago
July 20, 2022 at 10:47 PM UTC
Fixed (0.85.2)
4 years ago
July 20, 2022 at 07:53 PM UTC
Fixed (0.38.2)
4 years ago
July 20, 2022 at 07:54 PM UTC
Last Modified
1 year ago
May 02, 2025 at 12:48 PM UTC