Description
Wasmtime 47.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 contains an insufficient type-check in the TypedFunc embedder API for I31, Option<I31>, and Option<NoneRef> parameter or result types, reaching an unreachable!() path. A malicious guest module exporting a function that uses another anyref-hierarchy type can panic the host embedding, causing denial of service.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| bytecodealliance | wasmtime | 47.0.0 – < 48.0.8, 49.0.0 – < 49.0.5, 50.0.0 – < 50.0.1 | 48.0.8 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | rust-wasmtime | No fix yet | — |
| Ubuntu 26.04 LTS | rust-wasmtime | No fix yet | — |
| Ubuntu 24.04 LTS | rust-wasmtime | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| crates.io | wasmtime | >= 47.0.0, < 48.0.8 · >= 49.0.0, < 49.0.5 · >= 50.0.0, < 50.0.1 | 48.0.8, 49.0.5, 50.0.1 | RUSTSEC-2026-0422 |
References
- GitHub Security Advisory (GHSA-3982-jqvv-277m) vendor-advisory
- VulnCheck Advisory: Wasmtime 47.0.0 before 48.0.8 Denial of Service via TypedFunc Type-Check Panic third-party-advisory