Description
It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
References (4)
Core 4
Core References
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1656741
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-50/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-52/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-51/
Scores
CVSS v3
4.3
EPSS
0.0023
EPSS Percentile
46.0%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Details
CWE
CWE-1021
Status
published
Products (3)
mozilla/firefox
< 83.0
mozilla/firefox_esr
< 78.5
mozilla/thunderbird
< 78.5
Published
Dec 09, 2020
Tracked Since
Feb 18, 2026