{"action":"Upgrade firefox-esr to 78.5.0esr-1 or later.","affected":[{"fixed":"78.5.0esr-1","introduced":"0"}],"component":"firefox-esr","cve_ids":[],"ecosystem":"Debian","ecosystem_qualifier":"Debian:14","exploited":false,"fixed_versions":["78.5.0esr-1"],"id":"tcs_01M5NEXJSDCQ9DK7RFXS8R995R","modified_at":"2026-09-11T11:02:31.135768372Z","published_at":"2020-12-09T01:15:12.957Z","references":["https://osv.dev/vulnerability/DEBIAN-CVE-2020-26956","https://security-tracker.debian.org/tracker/CVE-2020-26956"],"severity":{"label":"medium","score":6.1},"sources":[{"source":"osv","source_id":"DEBIAN-CVE-2020-26956#Debian:14/firefox-esr","url":"https://osv.dev/vulnerability/DEBIAN-CVE-2020-26956"}],"summary":"In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird"}