Wasmtime: Preemption and traps during bulk operations enable breaking internal VM state
Summary
| CVE | CVE-2026-104855 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-02 18:17:02 UTC |
| Updated | 2026-10-02 18:17:02 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 2 LOW from [email protected]
CVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-362 | CWE-362 CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 2 | LOW | CVSS: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/C... |
| 4.0 | CNA | DECLARED | 2 | LOW | CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
PresentPrivileges Required
HighUser Interaction
PassiveConfidentiality
NoneIntegrity
LowAvailability
LowSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Bytecodealliance | Wasmtime | affected >= 46.0.0, < 46.0.2 | Not specified |
| CNA | Bytecodealliance | Wasmtime | affected >= 47.0.0, < 47.0.3 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/bytecodealliance/wasmtime/pull/14041 | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/commit/a3eb27af01ba5a30320a90ea1405... | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/releases/tag/v47.0.3 | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/pull/14043 | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/pull/14045 | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/releases/tag/v46.0.2 | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2hw9-mc66-... | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/commit/3ebfbe5af4927c157d6fcaca42b8... | [email protected] | github.com | |
| github.com/bytecodealliance/wasmtime/commit/99b0bc39d447317a4102c056081c... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.