Vulnerability · NVD
CVE-2025-3522
MEDIUM 6.3
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.
Attack vector : Network
No privileges required
Show raw CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
EPSS
0.26%
exploit very unlikely
percentile 17.4%
Tracked apps referencing this CVE
For each app: the affected range, the fixing version, and where the tracked app stands today.
Vulnerable CPE configurations (2)
| Vendor | Product | Platform | Versions | CPE 2.3 URI |
|---|---|---|---|---|
| mozilla |
thunderbird All platforms (wildcard)
|
All platforms (wildcard) | <128.9.2 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |
| mozilla |
thunderbird All platforms (wildcard)
|
All platforms (wildcard) | ≥129.0 <137.0.2 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |