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CVE-2025-6430

MEDIUMCVSS 6.1/10EPSS 0.21%

Last modified

CVE-2025-6430 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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.. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability
0.21%

11.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
MozillaFirefox< 128.12.0
MozillaFirefox< 140.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2025-6430?
When a file download is specified via the `Content-Disposition` header, that directive would be ignored if the file was included via a `&lt;embed&gt;` or `&lt;object&gt;` 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.
How severe is CVE-2025-6430?
CVE-2025-6430 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2025-6430?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-6430?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST