CVE-2023-6206: Debian Linux

Medium severity, CVSS 5.4. EPSS: 0.6% chance of exploitation in the next 30 days.

The black fade animation when exiting fullscreen is roughly the length of the anti-clickjacking delay on permission prompts. It was possible to use this fact to surprise users by luring them to click where the permission grant button would be about to appear. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only; version 12.0 only
• Mozilla Firefox: before 120.0 (fixed in 120.0)
• Mozilla Firefox ESR: before 115.5.0 (fixed in 115.5.0)
• Mozilla Thunderbird: before 115.5 (fixed in 115.5)

Published 2023-11-21. Last modified 2026-06-17.