Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 128.12.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1971140Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2025-51/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-53/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-54/
- https://www.mozilla.org/security/advisories/mfsa2025-55/
- https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html
- https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html
FAQ
What is CVE-2025-6430?
CVE-2025-6430 is a vulnerability with a CVSS score of 6.1 (MEDIUM). 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 web...
How severe is CVE-2025-6430?
CVE-2025-6430 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-6430?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox.