CVE-2026-115889

9.9 CRITICAL 0.5% exploit odds Fix listed Other

What it is

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend. This issue is fixed in versions 36.0.19 and 43.0.0.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-10-23 19:37 UTC ReservedThe CVE id was reserved by its CNA
2026-10-23 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-26 18:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.5% in the next 30 days (EPSS).
Severity: 9.9 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-10-23 22:16 UTC
Last modified: 2026-10-26 18:17 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-197
Record status: Deferred

Attack profile CVSS 3.1 · 9.9

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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-2026-115889.md and follow it. Check whether this project is affected by CVE-2026-115889. 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