---
id: "CVE-2026-109823"
kind: "vulnerability"
aliases: ["CVE-2026-109823"]
title: "Tidewave: local dev server leaks project filesystem paths via DNS rebinding"
severity: "low"
cvss: 2.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["elixir", "local-development", "package", "ruby", "tidewave"]
not_affected_if: ["already-on-0.9.2-or-later", "not-running-tidewave"]
published_at: "2026-10-27T16:17:29+00:00"
first_seen_at: "2026-10-27T16:33:07+00:00"
updated_at: "2026-10-27T16:34:28+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109823", "first_seen_at": "2026-10-27T16:33:07+00:00"}]
---

# Tidewave: local dev server leaks project filesystem paths via DNS rebinding

Tidewave, a development tool, exposes the names of filesystem paths in its configuration endpoint and rendered toolbar without checking the Host header. A web page that rebinds its domain to the loopback address can read those paths, which usually reveal the local username and project layout.

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

## How to check

- Check the installed tidewave version, for example `mix deps` or the lockfile entry, and confirm whether it is `0.8.0` or later but before `0.9.2`.
- Confirm whether the Tidewave dev server runs while a browser is open on the same machine.

## Fix

- Upgrade tidewave to `0.9.2` or later.

## Timeline

- 2026-10-27T16:33:07+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-109823

## From the sources

An attacker can read the name of filesystem paths of your application present via Tidewave configuration via /tidewave/connect or via the rendered toolbar.

Neither response checks the Host header. A web page that rebinds its own domain to the loopback address can therefore read the tag with a same-origin request, which carries no Origin header. The paths usually reveal the local username and the project layout.

This issue affects tidewave: from 0.8.0 before 0.9.2.

---

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