Race Condition Affecting rust-wasmtime package, versions <27.0.0+dfsg-2
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published14 Nov 2025
- disclosed12 Nov 2025
Introduced: 12 Nov 2025
NewCVE-2025-64345 (opens in a new tab)How to fix?
Upgrade Debian:unstable rust-wasmtime to version 27.0.0+dfsg-2 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream rust-wasmtime package and not the rust-wasmtime package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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.
References
- https://security-tracker.debian.org/tracker/CVE-2025-64345
- https://docs.rs/wasmtime/latest/wasmtime/struct.Memory.html#method.new
- https://docs.rs/wasmtime/latest/wasmtime/struct.SharedMemory.html#method.new
- https://docs.wasmtime.dev/stability-release.html
- https://github.com/bytecodealliance/wasmtime/commit/9ebb6934f00d58b92fb68ed0e0b16c0ae828ca10
- https://github.com/bytecodealliance/wasmtime/releases/tag/v38.0.4
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hc7m-r6v8-hg9q