---
id: "CVE-2026-119141"
kind: "vulnerability"
aliases: ["CVE-2026-119141"]
title: "Wasmtime: malicious Wasm module can crash the host process"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["plugin-hosts", "runtime", "rust", "wasmtime", "webassembly"]
not_affected_if: ["trusted-modules-only", "versions-outside-range"]
published_at: "2026-10-29T16:18:07+00:00"
first_seen_at: "2026-10-29T16:25:58+00:00"
updated_at: "2026-10-29T16:30:07+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119141", "first_seen_at": "2026-10-29T16:25:58+00:00"}]
---

# Wasmtime: malicious Wasm module can crash the host process

Wasmtime, a WebAssembly runtime, panics the host when a malicious Wasm module calls back into the host during a realloc while lowering stream or future results. An attacker who supplies a crafted module can crash the process that runs it, causing denial of service.

_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, for example `wasmtime --version` or the `wasmtime` crate version in `Cargo.lock`
- Flag versions in the affected ranges: `46.0.0` to before `48.0.6`, and `49.0.0` to before `49.0.3`

## Fix

- Upgrade to `48.0.6` on the 48 line
- Upgrade to `49.0.3` on the 49 line

## Timeline

- 2026-10-29T16:25:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119141

## From the sources

Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability that allows malicious Wasm modules to panic the host because the may_leave flag is not cleared during realloc. Attackers can call into the host from realloc while lowering stream or future results, such as cancelling the active read or re-waiting a waitable-set, crashing the host.

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