{"id":"CVE-2026-115889","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-115889","summary":"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…","details":"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.","published":"2026-10-23T21:23:27.669Z","modified":"2026-10-23T21:23:27.669Z","cvss":{"score":9.9,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/bytecodealliance/wasmtime/pull/12613","label":"bytecodealliance/wasmtime#12613"},"references":[{"type":"WEB","url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm-fmxm"},{"type":"WEB","url":"https://github.com/bytecodealliance/wasmtime/pull/12613"},{"type":"WEB","url":"https://github.com/bytecodealliance/wasmtime/pull/14818"},{"type":"WEB","url":"https://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9d03f4a438dae0"},{"type":"WEB","url":"https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa"},{"type":"WEB","url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19"},{"type":"WEB","url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v43.0.0"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-10-23T21:23:27.669Z"}}