{"action":"Upgrade thunderbird to 1:91.5.0-1 or later.","affected":[{"fixed":"1:91.5.0-1","introduced":"0"}],"component":"thunderbird","cve_ids":[],"ecosystem":"Debian","ecosystem_qualifier":"Debian:12","exploited":false,"fixed_versions":["1:91.5.0-1"],"id":"tcs_01M5NG04M1PPCRW5HSSGZFEG5T","modified_at":"2026-10-23T18:03:38.989439710Z","published_at":"2022-12-22T20:15:12.250Z","references":["https://osv.dev/vulnerability/DEBIAN-CVE-2021-4140","https://security-tracker.debian.org/tracker/CVE-2021-4140"],"severity":{"label":"critical","score":10},"sources":[{"source":"osv","source_id":"DEBIAN-CVE-2021-4140#Debian:12/thunderbird","url":"https://osv.dev/vulnerability/DEBIAN-CVE-2021-4140"}],"summary":"It was possible to construct specific XSLT markup that would be able to bypass an iframe sandbox. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5."}