{"cve":"CVE-2026-115889","nvd":{"published":"2026-10-23T22:16:58.400","modified":"2026-10-23T22:16:58.550","status":"Deferred","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.","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":["CWE-197","CWE-843"],"references":["https://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9d03f4a438dae0","https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa","https://github.com/bytecodealliance/wasmtime/pull/12613","https://github.com/bytecodealliance/wasmtime/pull/14818","https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19"],"products":[],"source":"nvd","synced_at":"2026-10-24T16:53:35.584907681+00:00"},"epss":{"cve":"CVE-2026-115889","score":0.00454,"percentile":0.39134,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-897f-g5gm-fmxm","url":"https://osv.dev/vulnerability/GHSA-897f-g5gm-fmxm","summary":"Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation","modified":"2026-10-23T22:25:51.511659839Z","packages":[{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":["<36.0.19"],"fixed":["36.0.19"]},{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=37.0.0 <43.0.0"],"fixed":["43.0.0"]}]},{"id":"RUSTSEC-2026-0380","url":"https://osv.dev/vulnerability/RUSTSEC-2026-0380","summary":"Bit-packing in Cranelift compiler causes silent overflow and miscompilation","modified":"2026-10-24T06:25:41Z","packages":[{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=0.0.0-0 <36.0.19",">=37.0.0 <43.0.0"],"fixed":["36.0.19","43.0.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}