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.

CVSS v3 5.0 MEDIUM

5.0^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.3 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2	Mitigation Vendor Advisory
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:bytecodealliance:wasmtime:43.0.0:*:*:*:*:rust:*:*

History

No history.

Information

Published : 2026-04-09 19:16

Updated : 2026-06-17 10:39

NVD link : CVE-2026-34983

Mitre link : CVE-2026-34983

CVE.ORG link : CVE-2026-34983

JSON object : View

Products Affected

bytecodealliance

wasmtime

CWE

CWE-416

Use After Free

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