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CVE PROGRAM SOURCE RECORD4.1 Medium

CVE-2026-34944

Wasmtime segfault or unused out-of-sandbox load with `f64x2.splat` operator on x86-64

Description

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but this data is not visible to WebAssembly guests. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

bytecodealliance wasmtime

  • < 24.0.7affected
  • >= 25.0.0, < 36.0.7affected
  • >= 37.0.0, < 42.0.2affected
  • >= 43.0.0, < 44.0.1affected

References