Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation

影響: rust:wasmtime < 36.0.19 → 36.0.19, rust:wasmtime >= 37.0.0, < 43.0.0 → 43.0.0

In 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…

在 GitHub Advisory Database 阅读

2026/10/24 07:02，GitHub Advisory Database 发布了“Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation”（类型：漏洞公告）。严重程度为“严重”（critical）。相关技术：Rust、Wasmtime / Wasmer。CVE：CVE-2026-115889。