CVE-2026-104855
Published:October 02, 2026
Updated:October 09, 2026
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.
Affected Packages
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v46.0.0 <v46.0.2Fix Suggestion:
Update to version v46.0.2https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v47.0.0 <v47.0.3Fix Suggestion:
Update to version v47.0.3wasmtime (RUST):
Affected version(s) >=46.0.0 <46.0.2Fix Suggestion:
Update to version 46.0.2wasmtime (RUST):
Affected version(s) >=47.0.0 <47.0.3Fix Suggestion:
Update to version 47.0.3Related Resources (14)
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Contact UsCVSS v4
Base Score:
2
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
HIGH
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
3.1
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
HIGH
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Weakness Type (CWE)
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
EPSS
Base Score:
0.28