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OpenAdvisories
Low · 1.8 CVE-2025-64345 EUVD-2025-131930GHSA-hc7m-r6v8-hg9qRUSTSEC-2025-0118

Wasmtime provides unsound API access to a WebAssembly shared linear memory

Published Nov 12, 2025 · Updated Nov 12, 2025 · Assigned by GitHub_M

Description

Wasmtime is a runtime for WebAssembly. Prior to version 38.0.4, 37.0.3, 36.0.3, and 24.0.5, Wasmtime's Rust embedder API contains an unsound interaction where a WebAssembly shared linear memory could be viewed as a type which provides safe access to the host (Rust) to the contents of the linear memory. This is not sound for shared linear memories, which could be modified in parallel, and this could lead to a data race in the host. Patch releases have been issued for all supported versions of Wasmtime, notably: 24.0.5, 36.0.3, 37.0.3, and 38.0.4. These releases reject creation of shared memories via `Memory::new` and shared memories are now excluded from core dumps. As a workaround, eembeddings affected by this issue should use `SharedMemory::new` instead of `Memory::new` to create shared memories. Affected embeddings should also disable core dumps if they are unable to upgrade. Note that core dumps are disabled by default but the wasm threads proposal (and shared memory) is enabled by default.

Affected products

VendorProductAffectedFixed
bytecodealliance wasmtime >= 38.0.1, < 38.0.4, >= 37.0.0, < 37.0.3, >= 26.0.0, < 36.0.3, < 24.0.5 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 rust-wasmtime 27.0.0+dfsg-2 —
Debian 13 rust-wasmtime No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 rust-wasmtime No fix yet —
Ubuntu 26.04 LTS rust-wasmtime No fix yet —
Ubuntu 25.10 rust-wasmtime No fix yet —
Ubuntu 24.04 LTS rust-wasmtime No fix yet —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling wash No fix yet —
Wolfi rolling wasmcloud 1.9.1-r0 —
Wolfi rolling wizer 10.0.0-r3 —
Wolfi rolling yara-x 1.9.0-r2 —
Wolfi rolling zed 0.228.0-r3 —
Wolfi rolling zellij 0.44.0-r0 —

Affected packages

EcosystemPackageAffectedFixedRecord
crates.io wasmtime >= 38.0.0, < 38.0.4 38.0.4 GHSA-hc7m-r6v8-hg9q
crates.io wasmtime >= 37.0.0, < 37.0.3 37.0.3 GHSA-hc7m-r6v8-hg9q
crates.io wasmtime >= 26.0.0, < 36.0.3 36.0.3 GHSA-hc7m-r6v8-hg9q
crates.io wasmtime < 24.0.5 24.0.5 GHSA-hc7m-r6v8-hg9q
crates.io wasmtime >= 0.0.0-0, < 24.0.5 · >= 25.0.0, < 36.0.3 · >= 37.0.0, < 37.0.3 · >= 38.0.0, < 38.0.4 24.0.5, 36.0.3, 37.0.3, 38.0.4 RUSTSEC-2025-0118

References