VULNERABILITY INTELLIGENCE
CVE-2026-115889
CVSS score9.9 CRITICAL
EPSS probability0.45%
CISA KEVNot currently listed
Published2026-10-23
Last modified2026-10-26
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Description
Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend. This issue is fixed in versions 36.0.19 and 43.0.0.
Weakness classification
- security-advisories@github.com: CWE-197