Live › vulnerability › CVE-2026-115889
Go to dashboardWasmtime's Cranelift compiler packs SSA value indices into bits, so large or crafted WebAssembly functions can overflow silently in release builds and produce incorrect code. The advisory says an attacker can use a specially crafted Wasm module to escape the sandbox.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 22:05 UTC, 2h before NVD. All times on this page are UTC.
| Product | Ecosystem | Affected | Fixed in |
|---|
| wasmtime | cargo | < 36.0.19 | 36.0.19 |
| wasmtime | cargo | >= 37.0.0, < 43.0.0 | 43.0.0 |
Run cargo tree -i wasmtime or check Cargo.lock for wasmtime versions below 36.0.19 or in the 37.0.0 to below 43.0.0 range.
Upgrade wasmtime to 36.0.19 if on the 36.x line, or to 43.0.0 if on the 37.x to 42.x line.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In Wasmtime prior to v43, the Cranelift compiler backend bit-packs its SSA value indices in a way that can result in silent overflow in release builds, and result in incorrect value references in the IR resulting in arbitrary miscompilation. A very large Wasm function body, or one that is specially crafted to use many SSA values, can use this to force type-confusion or other arbitrary side-effects and escape the sandbox.
Cranelift was changed in Wasmtime v43 to use a full u32 index, with checks if that limit is exceeded, and so is no longer susceptible to this bug.
A Wasmtime engine with default settings (using the Cranelift backend) on any architecture/platform could experience a sandbox escape from a specially-crafted Wasm module.
Wasmtime v36.0.19 has been released which fixes this issue.
This page as .md · .json · in your agent: get_signal("CVE-2026-115889")
GitHub Advisory Database, CC-BY 4.0 · NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.