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 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Exploit-prediction probability, daily snapshots since Oct 25.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CVEORG
0.7%
Last analysed / modified upstream
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.
Affected packages:
wasmtime >= 37.0.0, < 43.0.0Patched in:
wasmtime 43.0.0Connected by shared product, vendor, weakness, or advisory.
CVE-2026-115892Medium· 5.7Panic lowering a host-created component model stream into a guest that expects a different payload type
CVE-2026-115893Critical· 9.9Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction
RUSTSEC-2026-0380Critical· 9.9Bit-packing in Cranelift compiler causes silent overflow and miscompilation
CVE-2026-104855Low· 2.0Wasmtime is a runtime for WebAssembly
CVE-2023-41880Low· 2.2Miscompilation of wasm `i64x2.shr_s` instruction with constant input on x86\_64
CVE-2021-39216Medium· 6.3Out-of-bounds read/write and invalid free with `externref`s and GC safepoints in Wasmtime