CVE-2026-115889Critical· 9.9▾ MidnightWasmtime 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…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 54.5 · likelihood 0 · exploitation 0
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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.
wasmtime < 36.0.19wasmtime >= 37.0.0, < 43.0.0Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-115893Critical· 9.9Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction
CVE-2026-115892Medium· 5.7Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type
RUSTSEC-2026-0380Critical· 9.9Bit-packing in Cranelift compiler causes silent overflow and miscompilation
CVE-2026-115392High· 7.9Filesystem sandbox escape when paths or symlinks contain trailing slashes
CVE-2026-115393Low· 3.8Stores can mix up type indices between engines
CVE-2026-115391Medium· 5.8Guest controlled-size host heap allocation through WASIp3 streams