CVE-2026-104855

Description

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.

References

https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2hw9-mc66-jc2q

https://github.com/bytecodealliance/wasmtime/releases/tag/v47.0.3

https://github.com/bytecodealliance/wasmtime/releases/tag/v46.0.2

https://github.com/bytecodealliance/wasmtime/pull/14045

https://github.com/bytecodealliance/wasmtime/pull/14043

https://github.com/bytecodealliance/wasmtime/pull/14041

https://github.com/bytecodealliance/wasmtime/commit/a3eb27af01ba5a30320a90ea1405059cdfedd353

https://github.com/bytecodealliance/wasmtime/commit/99b0bc39d447317a4102c056081c83a9a84a46e0

https://github.com/bytecodealliance/wasmtime/commit/3ebfbe5af4927c157d6fcaca42b8dbb6d17b73fb

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-91765

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3

CVSS v4

EPSS