{"id":"CVE-2021-33829","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-33829","generatedAt":"2026-10-27T22:33:10.680Z","title":"A cross-site scripting (XSS) vulnerability in the HTML Data Processor in CKEditor 4 4.14.0 through 4.16.x before 4.16.1 allows remote attackers to inject executable JavaScript code through a crafted comment because --!> is mishandled.","description":"A cross-site scripting (XSS) vulnerability in the HTML Data Processor in CKEditor 4 4.14.0 through 4.16.x before 4.16.1 allows remote attackers to inject executable JavaScript code through a crafted comment because --!> is mishandled.","published":"2021-06-09T12:15:08.000Z","lastModified":"2026-06-17T03:55:17.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"cwe":["CWE-79"],"affected":["ckeditor/ckeditor","fedoraproject/fedora","drupal/drupal","debian/debian linux"],"epss":{"score":0.03189,"percentile":0.87998,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (3.19%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://ckeditor.com/blog/ckeditor-4.16.1-with-accessibility-enhancements/#improvements-for-comments-in-html-parser","tags":["Patch","Release Notes","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/11/msg00007.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NYA354LJP47KCVJMTUO77ZCX3ZK42G3T/","source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UVOYN2WKDPLKCNILIGEZM236ABQASLGW/","source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WAGNWHFIQAVCP537KFFS2A2GDG66J7XD/","source":"cve@mitre.org"},{"url":"https://www.drupal.org/sa-core-2021-003","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://ckeditor.com/blog/ckeditor-4.16.1-with-accessibility-enhancements/#improvements-for-comments-in-html-parser","tags":["Patch","Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/11/msg00007.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NYA354LJP47KCVJMTUO77ZCX3ZK42G3T/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UVOYN2WKDPLKCNILIGEZM236ABQASLGW/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WAGNWHFIQAVCP537KFFS2A2GDG66J7XD/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.drupal.org/sa-core-2021-003","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-33829","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}