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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- 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
CWEs
CWE-362
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.