CVE-2026-115889

Name of the Vulnerable Software and Affected Versions Wasmtime versions prior to 36.0.19 Wasmtime versions prior to 43.0.0

Description The Cranelift compiler backend bit-packs SSA (Static Single Assignment) value indices in a manner that can silently overflow in release builds. This occurs when compiling a specially crafted or sufficiently large Wasm function containing many SSA values. Such an overflow can lead to the referencing of incorrect IR (Intermediate Representation) values, resulting in arbitrary miscompilation and type confusion, which may allow an attacker to escape the Wasm sandbox on any architecture using the default Cranelift backend.

Recommendations Update to version 36.0.19. Update to version 43.0.0.