CVE-2021-4221: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 0.4% chance of exploitation in the next 30 days.

If a domain name contained a RTL character, it would cause the domain to be rendered to the right of the path. This could lead to user confusion and spoofing attacks. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*<br>*Note*: Due to a clerical error this advisory was not included in the original announcement, and was added in Feburary 2022. This vulnerability affects Firefox < 92.

Affected products

• Mozilla Firefox: before 92.0 (fixed in 92.0)

Published 2022-12-22. Last modified 2026-06-17.