{"id":"CVE-2026-115889","revision":"39902c0238d24337b217f78efb3490fe","records":[{"revision":"39902c0238d24337b217f78efb3490fe","observedAt":"2026-10-23T22:48:20.692+00:00","statement":{"source":"cve-program","id":"CVE-2026-115889","aliases":[],"title":"Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation","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.","state":0,"publishedAt":"2026-10-23T21:23:27.669+00:00","modifiedAt":"2026-10-23T21:23:27.669+00:00","affected":[{"ecosystem":"Vendor product","name":"wasmtime","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"bytecodealliance\",\n                    \"product\": \"wasmtime\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 36.0.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \">= 37.0.0, < 43.0.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":9.9,"severity":"CRITICAL"}],"references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm-fmxm","https://github.com/bytecodealliance/wasmtime/pull/12613","https://github.com/bytecodealliance/wasmtime/pull/14818","https://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9d03f4a438dae0","https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa","https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19","https://github.com/bytecodealliance/wasmtime/releases/tag/v43.0.0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-115889","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-115889","identifiers":["CVE-2026-115889"]},"retained":false,"historicalAffected":[]}],"coverage":[]}