CVE-2021-23996: Mozilla Firefox

Medium severity, CVSS 6.5. EPSS: 0.7% chance of exploitation in the next 30 days.

By utilizing 3D CSS in conjunction with Javascript, content could have been rendered outside the webpage's viewport, resulting in a spoofing attack that could have been used for phishing or other attacks on a user. This vulnerability affects Firefox < 88.

Affected products

• Mozilla Firefox: before 88.0 (fixed in 88.0)

Published 2021-06-24. Last modified 2026-06-17.