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    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.

    Published:Apr 9, 2026
    Last Modified:Apr 15, 2026
    EPS:Apr 9, 2026
    EPSS Score:0.00022
    CVSS Score:5

    Affected Products

    Vendor
    Bytecodealliance
    Product
    Wasmtime

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    No CAPEC recorded yet

    Related CVEs

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    CVE-2026-54786 (CVSS 2.3) — Wasmtime is a runtime for WebAssembly. All versions prior to 24.0.10; versions 25.0.0 through those before 36…
    CVE-2026-47261 (CVSS 7.5) — Wasmtime is a runtime for WebAssembly. In versions prior to 24.0.9, 36.0.10, and 44.0.2, when a filesystem pre…
    CVE-2026-44216 (CVSS 5.9) — Wasmtime is a runtime for WebAssembly. From 30.0.0 to 36.0.8, 43.0.2, and 44.0.1, Wasmtime's allocation logic …
    CVE-2026-35195 (CVSS 6.1) — Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation …
    CVE-2026-35186 (CVSS 6.1) — Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch comp…
    CVE-2026-34988 (CVSS 2.3) — Wasmtime is a runtime for WebAssembly. From 28.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementa…
    CVE-2026-34987 (CVSS 9) — Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime with its Win…
    CVE-2026-34971 (CVSS 9) — Wasmtime is a runtime for WebAssembly. From 32.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Cranelift …
    CVE-2026-34946 (CVSS 5.9) — Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch comp…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High