CVE-2026-34983 — Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`
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 program…
Published: 2026-04-09 · CVSS: 1.0 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7