CVE-2025-55028 JavaScript alerts could impede UI interaction or allow denial of service attacks

What is CVE-2025-55028?

CVE-2025-55028 is a medium-severity denial of service 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

Malicious scripts utilizing repetitive JavaScript alerts could prevent client user interaction in some scenarios and allow for denial of service attacks. This vulnerability was fixed in Firefox for iOS 142.

Weakness: CWE-400

Which versions are affected by CVE-2025-55028?

It affects 1 product.

Products include Mozilla Firefox.

How do I fix CVE-2025-55028?

No fix has been published for CVE-2025-55028 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2025-55028 being exploited?

There is no known exploitation of CVE-2025-55028 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-h3xr-99q8-227g.