CVE-2026-104855
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…
Does this matter?
Lower severity and a low EPSS score (0.28%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 2.0 LOWCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.28% probability · 20th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-362
- Source
- security-advisories@github.com
EPSS moved from 0.3% on 3 October 2026 to 0.3% on 26 October 2026.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.