CVE-2023-5726: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 0.6% 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. *Note: This issue only affected macOS operating systems. Other operating systems are unaffected.* This vulnerability affects Firefox < 119, Firefox ESR < 115.4, and Thunderbird < 115.4.1.

Affected products

• Mozilla Firefox: before 119.0 (fixed in 119.0)
• Mozilla Firefox ESR: before 115.4 (fixed in 115.4)
• Mozilla Thunderbird: before 115.4.1 (fixed in 115.4.1)

Published 2023-10-25. Last modified 2026-06-17.