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

Published Oct 27, 2026
·
Updated

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.

Affected Software

2 affected componentsFixes available
Mozilla Thunderbird<159
159
Mozilla Thunderbird<153.6
153.6

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 159
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 153.6
  3. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 159

Event History

Oct 27, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
CVE Published
via MITRE·06:16 PM
Data Sourced
via MITRE·06:16 PM
Description

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

Who is affected by this issue?

Users who subscribe Thunderbird to a malicious RSS feed are affected. Users of feeds delivered over HTTP are also exposed if an attacker can modify the feed in transit; on Windows, this can additionally expose NTLM credentials through a connection to an attacker-controlled network share.

2

What does an attacker need to exploit it?

The attacker needs to control a subscribed RSS feed or be able to alter a feed delivered over HTTP. The feed must provide an itunes:new-feed-url or newLocation redirect that changes the stored subscription URL to a file: URL.

3

What is the impact outside Windows?

On operating systems other than Windows, the described impact is limited to Thunderbird reading local files on each feed update. The NTLM credential leak through a network share is specific to Windows.

4

What can be done before upgrading?

Avoid subscribing to untrusted RSS feeds and avoid HTTP-delivered feeds where possible, since a party able to modify an HTTP feed can exploit the issue. Upgrade to Thunderbird 159, which contains the fix.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203