CVE-2025-64345CWE-362

CVE-2025-64345

Low · published November 13, 2025

CVSS v3.1
1.8
EPSS
0%
Percentile
1.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
1.8 · LOW
Vector
CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00116 · 1.5th percentile
Weakness
CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Published
2025-11-13T03:15Z
References (6)
EPSS history
Timeline
  • 12 NOV 21:25Z
    Wasmtime provides unsound API access to a WebAssembly shared linear memory
    cvelistv5