Type Confusion in Wasmtime - CVE-2026-34945
Published: April 10, 2026
Vulnerability identifier: #VU125756
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-34945
CWE-ID: CWE-843
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Bytecode Alliance
Affected software:
Wasmtime
Wasmtime
Detailed vulnerability description
The vulnerability allows a remote user to disclose sensitive information.
The vulnerability exists due to incorrect type handling in the Winch compiler's translation of the table.size instruction when processing WebAssembly code that uses 64-bit tables. A remote user can execute crafted WebAssembly code to disclose sensitive information.
Exploitation requires use of the memory64 proposal and can expose data from the host stack to a WebAssembly guest.
How to mitigate CVE-2026-34945
Install security update from vendor's website.