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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | — | 153.6 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | thunderbird | No fix yet | — |
| Debian 13 | thunderbird | 1:153.6.0esr-1~deb13u1 | — |
| Debian 12 | thunderbird | 1:153.6.0esr-1~deb12u2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | mozjs102 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | mozjs78 +3 | No fix yet | — |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaThunderbird | 153.6.0-1.1 | openSUSE-SU-2026:12339-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 153.6.0-1.amzn2.0.1 | ALAS2-2026-4105 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | thunderbird | 153.6.0-1.0.1.el10_2 | ELSA-2026-96079 |
| Oracle Linux 9 | thunderbird | 153.6.0-1.0.1.el9_8 | ELSA-2026-96081 |
Advisories 5
- WID-SEC-2026-4216 Mozilla Firefox, Firefox ESR, und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- ALAS2-2026-4105 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Nov 12, 2026
- ELSA-2026-96079 Important: thunderbird security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Nov 9, 2026
- ELSA-2026-96081 Important: thunderbird security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Nov 9, 2026
- openSUSE-SU-2026:12339-1 MozillaThunderbird-153.6.0-1.1 on GA media SUSE / openSUSE Security Updates · Oct 31, 2026