CVE-2025-23109 Address bar spoofing on iOS using long hostnames

What is CVE-2025-23109?

CVE-2025-23109 is a medium-severity vulnerability in Mozilla Firefox, published on 11 Jan 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

Long hostnames in URLs could be leveraged to obscure the actual host of the website or spoof the website address. This vulnerability was fixed in Firefox for iOS 134.

Weakness: CWE-346

Which versions are affected by CVE-2025-23109?

It affects 1 product.

Products include Mozilla Firefox.

How do I fix CVE-2025-23109?

No fix has been published for CVE-2025-23109 yet. Limit exposure of the affected software until one is available.

Is CVE-2025-23109 being exploited?

There is no known exploitation of CVE-2025-23109 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-6xcc-hv2v-v4r3.