---
id: "CVE-2026-119137"
kind: "vulnerability"
aliases: ["CVE-2026-119137"]
title: "Wasmtime: recursive type drops let a guest crash the host"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["runtime", "rust", "wasmtime", "webassembly"]
not_affected_if: ["no-wasmtime", "trusted-guests-only"]
published_at: "2026-10-29T16:18:07+00:00"
first_seen_at: "2026-10-29T16:25:58+00:00"
updated_at: "2026-10-29T16:30:08+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119137", "first_seen_at": "2026-10-29T16:25:58+00:00"}]
---

# Wasmtime: recursive type drops let a guest crash the host

Wasmtime versions 42.0.0 through 48.0.5 and 49.0.0 through 49.0.2 can be made to overflow the host stack when a guest defines a long chain of recursive types and that top-level type is removed. An attacker running untrusted WebAssembly guest code can crash the host process.

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

## How to check

- Run `wasmtime --version` (or check the Wasmtime crate version in `Cargo.lock`) and compare against the affected ranges 42.0.0 to before 48.0.6 and 49.0.0 to before 49.0.3.
- Check whether your application runs untrusted or user-supplied WebAssembly guests on Wasmtime.

## Fix

- Wasmtime `48.0.6` for the 48.x line
- Wasmtime `49.0.3` for the 49.x line

## Timeline

- 2026-10-29T16:25:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119137

## From the sources

Wasmtime 42.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a stack overflow vulnerability that allows guests to crash the host through recursive type drops. Guests can define a long chain of recursive types so that removing the top-level type triggers unbounded recursive drops, exhausting the host stack.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_