---
id: "CVE-2026-119134"
kind: "vulnerability"
aliases: ["CVE-2026-119134"]
title: "Wasmtime: guest code can exhaust host memory via resource handles"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["runtime", "rust", "wasmtime", "webassembly"]
not_affected_if: ["no-component-model", "trusted-guests-only"]
published_at: "2026-10-29T16:18:06+00:00"
first_seen_at: "2026-10-29T16:25:58+00:00"
updated_at: "2026-10-29T16:30:09+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119134", "first_seen_at": "2026-10-29T16:25:58+00:00"}]
---

# Wasmtime: guest code can exhaust host memory via resource handles

Wasmtime, the WebAssembly runtime, does not count component-model resource handles against the store's memory limits, so a malicious guest can repeatedly create resources and sub-components. This makes host memory grow without bound, which can crash the host process.

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

## Fix

- Wasmtime `36.0.18`
- Wasmtime `48.0.6`
- Wasmtime `49.0.3`

## Timeline

- 2026-10-29T16:25:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119134

## From the sources

Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 caps component-model resource handle tables only per component instance and does not charge handle allocations to any ResourceLimiter or StoreLimits. A malicious guest can repeatedly call resource.new and instantiate sub-components to exceed the per-instance cap many times over, causing unbounded host memory growth.

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