{"id":"CVE-2021-38506","details":"Through a series of navigations, Firefox could have entered fullscreen mode without notification or warning to the user. This could lead to spoofing attacks on the browser UI including phishing. This vulnerability affects Firefox \u003c 94, Thunderbird \u003c 91.3, and Firefox ESR \u003c 91.3.","modified":"2026-04-16T04:39:38.956519624Z","published":"2021-12-08T22:15:08.897Z","related":["ALSA-2021:4123","ALSA-2021:4130","SUSE-SU-2021:3651-1","SUSE-SU-2021:3721-1","SUSE-SU-2021:3745-1","SUSE-SU-2021:4150-1","openSUSE-SU-2021:1635-1","openSUSE-SU-2021:3745-1","openSUSE-SU-2021:4150-1","openSUSE-SU-2024:11607-1","openSUSE-SU-2024:11614-1","openSUSE-SU-2024:14572-1"],"references":[{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html"},{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html"},{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202208-14"},{"type":"ADVISORY","url":"https://www.debian.org/security/2022/dsa-5034"},{"type":"ADVISORY","url":"https://www.mozilla.org/security/advisories/mfsa2021-48/"},{"type":"ADVISORY","url":"https://www.mozilla.org/security/advisories/mfsa2021-50/"},{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202202-03"},{"type":"ADVISORY","url":"https://www.debian.org/security/2021/dsa-5026"},{"type":"ADVISORY","url":"https://www.mozilla.org/security/advisories/mfsa2021-49/"},{"type":"REPORT","url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1730750"}],"affected":[{"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"0"},{"fixed":"94.0"}]},{"events":[{"introduced":"0"},{"fixed":"91.3.0"}]},{"events":[{"introduced":"0"},{"fixed":"91.3.0"}]},{"events":[{"introduced":"0"},{"last_affected":"9.0"}]},{"events":[{"introduced":"0"},{"last_affected":"10.0"}]},{"events":[{"introduced":"0"},{"last_affected":"11.0"}]}],"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-38506.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"}]}