CVE-2025-3029 URL Bar Spoofing via non-BMP Unicode characters

What is CVE-2025-3029?

CVE-2025-3029 is a high-severity vulnerability in Mozilla Firefox, published on 1 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A crafted URL containing specific Unicode characters could have hidden the true origin of the page, resulting in a potential spoofing attack. This vulnerability was fixed in Firefox 137, Firefox ESR 128.9, Thunderbird 137, and Thunderbird 128.9.

Weakness: CWE-290

Which versions are affected by CVE-2025-3029?

It affects 2 products.

Products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2025-3029?

Upgrade to a fixed version.

Is CVE-2025-3029 being exploited?

There is no known exploitation of CVE-2025-3029 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 DEBIAN-CVE-2025-3029, GHSA-799g-3g44-3g9m, UBUNTU-CVE-2025-3029.