CVE-2025-64345

LOW

Crates.io Wasmtime < 38.0.4 - Race Condition

Title source: rule

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.

Scores

CVSS v3 1.8
EPSS 0.0001
EPSS Percentile 1.6%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N

Classification

CWE
CWE-362
Status draft

Affected Products (1)

crates.io/wasmtime < 38.0.4crates.io

Timeline

Published Nov 12, 2025
Tracked Since Feb 18, 2026