CVE-2025-1015: Mozilla Thunderbird

Medium severity, CVSS 5.4. EPSS: 1.4% chance of exploitation in the next 30 days.

The Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If another user imported the address book, clicking on the link could result in opening a web page inside Thunderbird, and that page could execute (unprivileged) JavaScript. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135.

Affected products

• Mozilla Thunderbird: from 128.0.1, before 128.7.0 (fixed in 128.7.0)

Published 2025-02-04. Last modified 2026-06-17.