CVE-2026-34944

Summary

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 Software

VendorProductVersion RangeStatus
bytecodealliancewasmtime< 24.0.7affected
bytecodealliancewasmtime>= 25.0.0, < 36.0.7affected
bytecodealliancewasmtime>= 37.0.0, < 42.0.2affected
bytecodealliancewasmtime>= 43.0.0, < 44.0.1affected

Weaknesses

  • CWE-248: CWE-248: Uncaught Exception

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References