---
id: "CVE-2026-119130"
kind: "vulnerability"
aliases: ["CVE-2026-119130"]
title: "Wasmtime: WASI HTTP guests can reach hosts outside embedder allowlists"
severity: "low"
cvss: 2.6
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["runtime", "wasi-http", "wasmtime", "webassembly"]
not_affected_if: ["no-forward-proxy", "no-untrusted-guests", "no-wasi-http"]
published_at: "2026-10-29T16:18:05+00:00"
first_seen_at: "2026-10-29T16:25:58+00:00"
updated_at: "2026-10-29T16:32:12+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119130", "first_seen_at": "2026-10-29T16:25:58+00:00"}]
---

# Wasmtime: WASI HTTP guests can reach hosts outside embedder allowlists

Wasmtime's wasmtime-wasi-http does not check that set-path-with-query values are paths, so absolute-form URLs are sent as the HTTP/1.1 request target. A malicious guest can use this to make a forward proxy or gateway reach hosts the embedder's filtering policy disallows.

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

## How to check

- Check the Wasmtime version in use, e.g. `wasmtime --version`, and compare it against the affected ranges below.
- Look for embedders that use wasmtime-wasi-http and rely on outbound host allowlists or forward proxies.

## Fix

- `wasmtime` before `36.0.18` fixed to `36.0.18`
- `wasmtime` `37.0.0` before `48.0.6` fixed to `48.0.6`
- `wasmtime` `49.0.0` before `49.0.3` fixed to `49.0.3`

## Timeline

- 2026-10-29T16:25:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119130

## From the sources

Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 does not verify that set-path-with-query values in wasmtime-wasi-http are paths, so absolute-form URLs are written verbatim as the HTTP/1.1 request target while the connection uses the allowed authority. A malicious guest can supply an absolute URL that a forward proxy or gateway at that authority honors, reaching hosts disallowed by embedder filtering policies.

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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_