{"id":"ghsa-ghsa-897f-g5gm-fmxm","seq":661298,"kind":"advisory","title":"Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation","url":"https://github.com/advisories/GHSA-897f-g5gm-fmxm","permalink":"https://vulnpulse.app/items/ghsa-ghsa-897f-g5gm-fmxm","summary":"影響: rust:wasmtime < 36.0.19 → 36.0.19, rust:wasmtime >= 37.0.0, < 43.0.0 → 43.0.0\nIn Wasmtime prior to v43, the Cranelift compiler backend bit-packs its SSA value indices in a way that can result in silent overflow in release builds, and result in incorrect value references in the IR resulting in arbitrary miscompilation. A very large Wasm function body, or one that is specially crafted to use many SSA values, can use this to force type-confusion or other arbitrary side-effects and escape the sandbox. Cranelift was changed in Wasmtime v43 to use a full u32 index, with checks…","severity":"critical","techs":["rust","wasmtime"],"cves":["CVE-2026-115889"],"tags":["GHSA-897f-g5gm-fmxm","wasmtime","wasmtime"],"source":{"id":"ghsa","name":"GitHub Advisory Database"},"published_at":"2026-10-23T22:02:20.000Z","fetched_at":"2026-10-24T04:50:51.468Z"}