CVE-2026-104855

Wasmtime is a runtime for WebAssembly. From 46.0.0 until 46.0.2 and 47.0.3, fuel and epoch preemption checks inside bulk operations including memory.copy, table.grow, and array.copy can expose invalid intermediate state when an embedder mutates a Store in Store::epoch_deadline_callback or continues using a Store after cancellation or a trap. A cancelled non-nullable table growth can leave null elements, linear-memory growth during memory.copy can invalidate retained raw pointers, and callback-triggered garbage collection during array.copy can invalidate GC pointers, resulting in a crash, invalid memory access, or GC heap corruption. Embeddings whose callbacks only access the host data in Store<T>, and embeddings that discard a Store after timeout or epoch deadline, are not affected. This issue is fixed in versions 46.0.2 and 47.0.3.

CVSS

No CVSS.

References

Link	Resource
https://github.com/bytecodealliance/wasmtime/commit/3ebfbe5af4927c157d6fcaca42b8dbb6d17b73fb
https://github.com/bytecodealliance/wasmtime/commit/99b0bc39d447317a4102c056081c83a9a84a46e0
https://github.com/bytecodealliance/wasmtime/commit/a3eb27af01ba5a30320a90ea1405059cdfedd353
https://github.com/bytecodealliance/wasmtime/pull/14041
https://github.com/bytecodealliance/wasmtime/pull/14043
https://github.com/bytecodealliance/wasmtime/pull/14045
https://github.com/bytecodealliance/wasmtime/releases/tag/v46.0.2
https://github.com/bytecodealliance/wasmtime/releases/tag/v47.0.3
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2hw9-mc66-jc2q

Configurations

No configuration.

History

02 Oct 2026, 18:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-02 18:17

Updated : 2026-10-06 17:17

NVD link : CVE-2026-104855

Mitre link : CVE-2026-104855

CVE.ORG link : CVE-2026-104855

JSON object : View

Products Affected

No product.

CWE

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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