CVE-2026-34983 LOW

CVE-2026-34983: Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`

Vendor Bytecodealliance
Product wasmtime
Weakness CWE-416
Published April 9, 2026
Last update April 13, 2026
View on NVD All CVEs

CVSS base score

1.0/10
Attack vector Physical
Attack complexity High
Privileges required High
User interaction —
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:P/AC:H/AT:P/PR:H/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Wasmtime is a runtime for WebAssembly. In 43.0.0, cloning a wasmtime::Linker is unsound and can result in use-after-free bugs. This bug is not controllable by guest Wasm programs. It can only be triggered by a specific sequence of embedder API calls made by the host. Specifically, the following steps must occur to trigger the bug clone a wasmtime::Linker, drop the original linker instance, use the new, cloned linker instance, resulting in a use-after-free. This vulnerability is fixed in 43.0.1.

Key dates

02Disclosure timeline

April 9, 2026 CVE published
April 13, 2026 Record updated