CVE-2021-23996

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-06-24 · updated 2026-06-17

Description

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

How to fix

Upgrade to a fixed version: Mozilla Firefox 88.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1701834
https://www.mozilla.org/security/advisories/mfsa2021-16/
https://bugzilla.mozilla.org/show_bug.cgi?id=1701834
https://www.mozilla.org/security/advisories/mfsa2021-16/

Get alerted when CVE-2021-23996 or the next vulnerability affects your stack