CVE-2025-55030 Content-Disposition headers incorrectly ignored for some MIME types

What is CVE-2025-55030?

CVE-2025-55030 is a medium-severity cross-site scripting vulnerability in Mozilla Firefox, published on 19 Aug 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Firefox for iOS would not respect a Content-Disposition header of type Attachment and would incorrectly display the content inline rather than downloading, potentially allowing for XSS attacks. This vulnerability was fixed in Firefox for iOS 142.

Weakness: CWE-640

Which versions are affected by CVE-2025-55030?

It affects 1 product.

Products include Mozilla Firefox.

How do I fix CVE-2025-55030?

No fix has been published for CVE-2025-55030 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-55030 being exploited?

There is no known exploitation of CVE-2025-55030 in the wild and no public exploit code.

Other vulnerabilities in Mozilla Firefox

• CVE-2019-11708 Mozilla Firefox and Thunderbird Sandbox Escape Exploited Critical 10.0
• CVE-2010-3765 Mozilla Multiple Products Remote Code Execution Exploited Critical 9.8
• CVE-2022-26486 Mozilla Firefox Use-After-Free Exploited Critical 9.6
• CVE-2022-26485 Mozilla Firefox Use-After-Free Exploited High 8.8
• CVE-2019-11707 Mozilla Firefox and Thunderbird Type Confusion Exploited High 8.8

All Mozilla Firefox vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-jhw6-rcq8-2vxj.