CVE-2017-7770: Mozilla Firefox

Medium severity, CVSS 5.9. EPSS: 1.1% chance of exploitation in the next 30 days.

A mechanism where when a new tab is loaded through JavaScript events, if fullscreen mode is then entered, the addressbar will not be rendered. This would allow a malicious site to displayed a spoofed addressbar, showing the location of an arbitrary website instead of the one loaded. Note: this issue only affects Firefox for Android. Desktop Firefox is unaffected. This vulnerability affects Firefox < 54.

Affected products

• Mozilla Firefox: before 54.0 (fixed in 54.0)

Published 2018-06-11. Last modified 2026-06-17.