github.com
https://github.com/bytecodealliance/wasmtime CVE-2026-34983
LOW
Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`
Record summary
CVE-2026-34983 has a selected CVSS score of 1.0 (low).
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.
Description source: CVE List
Exploitation context
CISA SSVC decision
ExploitationPoC
AutomatableNo
Technical impactPartial
CISA Coordinator · SSVC 2.0.3 · Evaluated Apr 13, 2026 · Source: CVE List
Affected products and versions
2| Product | Source | Version range | Status |
|---|---|---|---|
| CVE List | >= 43.0.0, < 43.0.1 | affected | |
wasmtimeBrowse crates.io / wasmtime | GitHub Advisory | 43.0.0 | affected |
| 43.0.0 to < 43.0.1 · Fixed in 43.0.1 | affected |
References
5github.comConfirmation
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2 github.com
https://github.com/pypa/advisory-database/tree/main/vulns/wasmtime/PYSEC-2026-151.yaml nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-34983 rustsec.org
https://rustsec.org/advisories/RUSTSEC-2026-0090.html