---
id: "CVE-2026-119132"
kind: "vulnerability"
aliases: ["CVE-2026-119132"]
title: "Wasmtime: overlapping strings in fused adapters let a guest crash the host"
severity: "medium"
cvss: 5.9
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["component-model", "runtime", "wasmtime", "webassembly"]
not_affected_if: ["not-on-affected-versions", "trusted-modules-only"]
published_at: "2026-10-29T16:18:06+00:00"
first_seen_at: "2026-10-29T16:25:58+00:00"
updated_at: "2026-10-29T16:31:42+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119132", "first_seen_at": "2026-10-29T16:25:58+00:00"}]
---

# Wasmtime: overlapping strings in fused adapters let a guest crash the host

Wasmtime from 49.0.0 before 49.0.3 panics the host when a WebAssembly guest transfers a string whose source and destination overlap during a same-instance component call. The result is a denial of service: the host process crashes instead of raising a trap.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the Wasmtime version in your build or lockfile; affected versions are `49.0.0` up to but not including `49.0.3`.
- Find where Wasmtime is embedded in your services and whether it runs untrusted WebAssembly components.

## Fix

- Wasmtime: move to `49.0.3` or later.

## Timeline

- 2026-10-29T16:25:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119132

## From the sources

Wasmtime from 49.0.0 before 49.0.3 contains a denial-of-service vulnerability that allows a WebAssembly guest to trigger a host panic by transcoding overlapping strings in fused adapters. Attackers can make a same-instance component-to-component call transferring a string whose source and destination alias each other, crashing the host instead of raising a trap.

---

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