---
cve: "CVE-2026-115889"
severity: "CRITICAL"
cvss: 9.9
epss: "0.4%"
vendor: "bytecodealliance"
kev: false
exploited: false
published: "2026-10-23 22:16:58"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-11-01T18:20:05+01:00"
---

# CVE-2026-115889

> 9.9 CRITICAL · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **GitHub_M**
- State: PUBLISHED
- Stand: 2026-10-26 17:42:15
- CNA-CVSS: **9.9** (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Schwachstellen-Klasse

- **CWE-197** — Numeric Truncation Error
  Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.
- **CWE-843** — Access of Resource Using Incompatible Type ('Type Confusion')
  The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

## Patch verfügbar (OSV)

- 0d6b8ead4e94b0ce76f925611b831b56570aef94 (Commit)
- be23469ece57c0be64904f12111c8d808b0ce4ac (Commit)

## Referenzen

- <https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm-fmxm>
- <https://github.com/bytecodealliance/wasmtime/pull/12613>
- <https://github.com/bytecodealliance/wasmtime/pull/14818>
- <https://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9d03f4a438dae0>
- <https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa>
- <https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19>
- <https://github.com/bytecodealliance/wasmtime/releases/tag/v43.0.0>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-115889/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_