CVE-2025-6430: Vulnerability in Mozilla Firefox
When a file download is specified via the `Content-Disposition` header, that directive would be ignored if the file was included via a `<embed>` or `<object>` tag, potentially making a website vulnerable to a cross-site scripting attack. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
AI Analysis
Technical Summary
This vulnerability occurs because Firefox ignored the Content-Disposition header's file download directive when the file was embedded using <embed> or <object> HTML tags. This could allow an attacker to bypass intended download behavior and potentially execute cross-site scripting attacks on affected websites. The flaw was reported by Daniil Satyaev of Positive Technologies and is tracked as CVE-2025-6430. It was addressed and fixed in Firefox 140 and Firefox ESR 128.12.
Potential Impact
The vulnerability could allow an attacker to perform cross-site scripting attacks by embedding files in a way that bypasses the Content-Disposition header's download directive. This can lead to partial compromise of confidentiality and integrity (CVSS 6.1, impact on confidentiality and integrity). There are no reports of active exploitation in the wild.
Mitigation Recommendations
This vulnerability has been fixed in Firefox 140 and Firefox ESR 128.12. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation steps are required as the fix is official and complete.
CVE-2025-6430: Vulnerability in Mozilla Firefox
Description
When a file download is specified via the `Content-Disposition` header, that directive would be ignored if the file was included via a `<embed>` or `<object>` tag, potentially making a website vulnerable to a cross-site scripting attack. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability occurs because Firefox ignored the Content-Disposition header's file download directive when the file was embedded using <embed> or <object> HTML tags. This could allow an attacker to bypass intended download behavior and potentially execute cross-site scripting attacks on affected websites. The flaw was reported by Daniil Satyaev of Positive Technologies and is tracked as CVE-2025-6430. It was addressed and fixed in Firefox 140 and Firefox ESR 128.12.
Potential Impact
The vulnerability could allow an attacker to perform cross-site scripting attacks by embedding files in a way that bypasses the Content-Disposition header's download directive. This can lead to partial compromise of confidentiality and integrity (CVSS 6.1, impact on confidentiality and integrity). There are no reports of active exploitation in the wild.
Mitigation Recommendations
This vulnerability has been fixed in Firefox 140 and Firefox ESR 128.12. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation steps are required as the fix is official and complete.
Technical Details
- Data Version
- 5.1
- Assigner Short Name
- mozilla
- Date Reserved
- 2025-06-20T14:51:35.561Z
- Cvss Version
- null
- State
- PUBLISHED
Threat ID: 685aa0274dc24046c1dc5aa9
Added to database: 6/24/2025, 12:55:03 PM
Last enriched: 4/14/2026, 11:51:58 AM
Last updated: 5/9/2026, 11:17:05 PM
Views: 94
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