Use After Free in Bytecodealliance Cranelift-Codegen
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.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L.
EPSS exploit prediction
EPSS: 0.013 (69.0th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 69.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.013 · change: +0.000
Affected products
- Bytecodealliance Cranelift-Codegen
- Bytecodealliance Wasmtime — versions >= 0.37.0, < 0.38.2, >= 0.84.0, < 0.85.2
Weakness classification (CWE)
References
- github.com/bytecodealliance/wasmtime/security/advisories/GHSA-5fhj-g3p3-pq9g (Third Party Advisory, Mitigation)
- github.com/WebAssembly/reference-types (Third Party Advisory)
- github.com/bytecodealliance/wasmtime/ (Product, Third Party Advisory)
Frequently asked questions
- What is CVE-2022-31146?
- CVE-2022-31146 is a medium-severity vulnerability in Bytecodealliance Cranelift-Codegen, classified under Use After Free. CVSS score: 6.4/10. Published 2022-07-21.
- How severe is CVE-2022-31146?
- Medium severity. CVSS v3 base score is 6.4 out of 10.