Out-of-bounds read in Wasmtime - CVE-2026-34944
Published: April 10, 2026
Vulnerability identifier: #VU125758
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-34944
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to an out-of-bounds read in Cranelift's compilation of the f64x2.splat WebAssembly instruction on x86-64 when processing a memory-loaded value without SSE3. A local user can execute crafted WebAssembly that triggers the widened load to cause a denial of service.
Exploitation requires guard pages to be enabled and signals-based-traps to be disabled. User interaction is required.
Affected software
Wasmtime
How to mitigate CVE-2026-34944
Install security update from vendor's website.
Wasmtime - addressed in versions 24.0.7, 36.0.7, 42.0.2, 43.0.1