Race Condition Affecting wasmtime package, versions >=46.0.0 <46.0.2>=47.0.0 <47.0.3
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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Test your applications- Snyk IDSNYK-RUST-WASMTIME-21708419
- published25 Oct 2026
- disclosed2 Oct 2026
- creditUnknown
Introduced: 2 Oct 2026
NewCVE-2026-104855 (opens in a new tab)How to fix?
Upgrade wasmtime to version 46.0.2, 47.0.3 or higher.
Overview
Affected versions of this package are vulnerable to Race Condition in the handling of bulk WebAssembly operations such as memory.copy, array.copy, and table.grow when preemption via epochs or fuel occurs and the store's state is mutated or computation is cancelled. An attacker can cause the internal state to become inconsistent or uninitialized by triggering preemption and then mutating the store or resuming execution, potentially leading to memory corruption or segmentation faults. This is only exploitable if the embedding uses Store::epoch_deadline_callback and mutates the store during the callback, or resumes execution after a computation is cancelled.
Workaround
This vulnerability can be mitigated by ensuring embedders only access the T in Store<T> during Store::epoch_deadline_callback and by not continuing to use a store after a timeout or epoch deadline.