CVE-2026-104855

2.0 LOW 0.3% exploit odds Fix listed Denial of service

What it is

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.

At a glance

Exploitability: Can be exploited over the network with an admin-level account, but needs a user to act. Limited direct impact.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-10-02 18:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-06 17:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 2.0 LOW (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-10-02 18:17 UTC
Last modified: 2026-10-06 17:17 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-362 · Race condition
Record status: Deferred

Attack profile CVSS 4.0 · 2.0

Attack vector: Network
Complexity: High
Attack requirements: Present
Privileges needed: High
User interaction: Passive
Confidentiality: None
Integrity: Low
Availability: Low

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-104855.md and follow it. Check whether this project is affected by CVE-2026-104855. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record