Vulnerability Details CVE-2026-34983
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 5.9%
CVSS Severity
CVSS v3 Score 5.0
References
Products affected by CVE-2026-34983
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cpe:2.3:a:bytecodealliance:wasmtime:43.0.0