CVE-2026-34983
Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`
- State
- Published
- Severity
- 1.0 Low
- Published
- Apr 9, 2026
- Updated
- Apr 13, 2026
- Reserved
- Mar 31, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 1.0 Low | 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 | GitHub_M |
Weaknesses
- CWE-416 Use After Free
Affected Products
| Product | Versions |
|---|---|
wasmtimebytecodealliance |
|
References
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