---
id: "CVE-2026-118178"
kind: "vulnerability"
aliases: ["CVE-2026-118178"]
title: "Thunderbird: RSS feed redirect reads local files and leaks NTLM credentials"
severity: "high"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["desktop", "package", "thunderbird", "windows"]
not_affected_if: ["no-rss-subscriptions"]
published_at: "2026-10-27T19:17:29+00:00"
first_seen_at: "2026-10-27T19:33:18+00:00"
updated_at: "2026-10-27T19:35:05+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118178", "first_seen_at": "2026-10-27T19:33:18+00:00"}]
---

# Thunderbird: RSS feed redirect reads local files and leaks NTLM credentials

A malicious RSS feed can use the itunes:new-feed-url or newLocation element to permanently change its stored subscription URL to a file: location, so Thunderbird reads that local file on every update. On Windows, the same redirect can point at an attacker-controlled network share and leak the user's NTLM credentials.

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

## How to check

- Check the installed Thunderbird version with Help > About Thunderbird, or `thunderbird --version` on the command line
- Review RSS subscriptions for any feed URL beginning with file: or a network share path

## Fix

- Update Thunderbird to `159` or `153.6`, or a later release of either line

## Timeline

- 2026-10-27T19:33:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118178

## From the sources

A remote RSS feed could use the itunes:new-feed-url or newLocation element to permanently change its stored subscription URL to a file: URL. Thunderbird then read that location on every feed update. This allowed a malicious feed, or an attacker able to modify a feed delivered over HTTP, to make Thunderbird read local files and, on Windows, connect to an attacker-controlled network share, which could leak the user's NTLM credentials.
The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are affected by the local file read only. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

---

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