Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.
CVSS Details
- CVSS 3.1 Base Score: 6.3
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade thunderbird | Apr 29, 2025 | Apr 15, 2025 |
| Amazon Linux Ami 2 | — | Upgrade thunderbirdUpgrade thunderbird-debuginfo | May 30, 2025 | Apr 15, 2025 |
| Debian | — | Upgrade thunderbird | May 5, 2025 | Apr 15, 2025 |
| Mozilla Thunderbird | — | Upgrade to Mozilla Thunderbird version 128.9.2 | Apr 16, 2025 | Apr 15, 2025 |
| Oracle_linux | — | Upgrade thunderbird | Apr 29, 2025 | Apr 15, 2025 |
| Redhat_linux | — | Upgrade thunderbird-debugsourceNo solution existsUpgrade thunderbirdUpgrade thunderbird-debuginfo | Apr 29, 2025 | Apr 15, 2025 |
| Rocky_linux | — | Upgrade thunderbirdUpgrade thunderbird-debugsourceUpgrade thunderbird-debuginfo | Jul 31, 2025 | Jul 29, 2025 |
| Suse | — | Upgrade mozillathunderbird-translations-commonUpgrade mozillathunderbirdUpgrade mozillathunderbird-translations-other | Apr 25, 2025 | Apr 15, 2025 |
| Ubuntu | — | Upgrade thunderbird | Jul 23, 2025 | Apr 15, 2025 |
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