CVE - CVE-2025-3522

CVE-ID
CVE-2025-3522	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
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 affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://bugzilla.mozilla.org/show_bug.cgi?id=1955372 URL:https://bugzilla.mozilla.org/show_bug.cgi?id=1955372 MISC:https://www.mozilla.org/security/advisories/mfsa2025-26/ URL:https://www.mozilla.org/security/advisories/mfsa2025-26/ MISC:https://www.mozilla.org/security/advisories/mfsa2025-27/ URL:https://www.mozilla.org/security/advisories/mfsa2025-27/
Assigning CNA
Mozilla Corporation
Date Record Created
20250411	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250411)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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