medium5.7
CVE-2026-34944
Wasmtime segfault or unused out-of-sandbox load with `f64x2.splat` operator on x86-64
Impact
Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but this data is not visible to WebAssembly guests. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rust | wasmtime | < 24.0.7 | 24.0.7 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Bytecodealliance | Wasmtime | before 24.0.7 from 25.0.0 before 36.0.7 from 37.0.0 before 42.0.2 from 43.0.0 before 43.0.1 |