{"id":"DEBIAN-CVE-2020-26953","details":"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 \u003c 83, Firefox ESR \u003c 78.5, and Thunderbird \u003c 78.5.","modified":"2026-09-01T16:05:00.481856464Z","published":"2020-12-09T01:15:12.770Z","upstream":["CVE-2020-26953"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2020-26953"}],"affected":[{"package":{"name":"firefox-esr","ecosystem":"Debian:12","purl":"pkg:deb/debian/firefox-esr?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"78.5.0esr-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26953.json"}},{"package":{"name":"firefox-esr","ecosystem":"Debian:13","purl":"pkg:deb/debian/firefox-esr?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"78.5.0esr-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26953.json"}},{"package":{"name":"firefox-esr","ecosystem":"Debian:14","purl":"pkg:deb/debian/firefox-esr?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"78.5.0esr-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26953.json"}},{"package":{"name":"thunderbird","ecosystem":"Debian:12","purl":"pkg:deb/debian/thunderbird?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:78.5.0-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26953.json"}},{"package":{"name":"thunderbird","ecosystem":"Debian:13","purl":"pkg:deb/debian/thunderbird?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:78.5.0-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26953.json"}},{"package":{"name":"thunderbird","ecosystem":"Debian:14","purl":"pkg:deb/debian/thunderbird?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:78.5.0-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-26953.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"}]}