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
                    | Link | Resource | 
|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1955372 | Permissions Required | 
| https://www.mozilla.org/security/advisories/mfsa2025-26/ | Vendor Advisory | 
| https://www.mozilla.org/security/advisories/mfsa2025-27/ | Vendor Advisory | 
Configurations
                    Configuration 1 (hide)
| 
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History
                    18 Jun 2025, 13:26
| Type | Values Removed | Values Added | 
|---|---|---|
| First Time | Mozilla Mozilla thunderbird | |
| References | () https://bugzilla.mozilla.org/show_bug.cgi?id=1955372 - Permissions Required | |
| References | () https://www.mozilla.org/security/advisories/mfsa2025-26/ - Vendor Advisory | |
| References | () https://www.mozilla.org/security/advisories/mfsa2025-27/ - Vendor Advisory | |
| CPE | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | |
| Summary | 
 | 
15 Apr 2025, 19:16
| Type | Values Removed | Values Added | 
|---|---|---|
| CVSS | v2 : v3 : | v2 : unknown v3 : 6.3 | 
| CWE | CWE-601 | 
15 Apr 2025, 15:16
| Type | Values Removed | Values Added | 
|---|---|---|
| New CVE | 
Information
                Published : 2025-04-15 15:16
Updated : 2025-06-18 13:26
NVD link : CVE-2025-3522
Mitre link : CVE-2025-3522
CVE.ORG link : CVE-2025-3522
JSON object : View
Products Affected
                mozilla
- thunderbird
CWE
                
                    
                        
                        CWE-601
                        
            URL Redirection to Untrusted Site ('Open Redirect')
