CVE-2023-4051: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

A website could have obscured the full screen notification by using the file open dialog. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 116, Firefox ESR < 115.2, and Thunderbird < 115.2.

Affected products

• Mozilla Firefox: before 116.0 (fixed in 116.0)

Published 2023-08-01. Last modified 2026-06-17.