{"id":"UBUNTU-CVE-2021-33829","details":"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 --!\u003e is mishandled.","modified":"2026-01-30T02:49:48.553695Z","published":"2021-06-09T12:15:00Z","related":["USN-5340-1","USN-5340-2"],"upstream":["CVE-2021-33829"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-33829"},{"type":"REPORT","url":"https://ckeditor.com/blog/ckeditor-4.16.1-with-accessibility-enhancements/#improvements-for-comments-in-html-parser"},{"type":"REPORT","url":"https://github.com/ckeditor/ckeditor4/commit/3e426ce34f7fc7bf784624358831ef9e189bb6ed"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5340-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-33829"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5340-2"}],"affected":[{"package":{"name":"ckeditor","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/ckeditor@4.5.7+dfsg-2ubuntu0.16.04.1~esm1?arch=source&distro=esm-apps/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.5.7+dfsg-2ubuntu0.16.04.1~esm1"}]}],"versions":["4.4.4+dfsg1-3","4.5.6+dfsg-1","4.5.7+dfsg-1","4.5.7+dfsg-2"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"ckeditor","binary_version":"4.5.7+dfsg-2ubuntu0.16.04.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-33829.json"}},{"package":{"name":"ckeditor","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/ckeditor@4.5.7+dfsg-2ubuntu0.18.04.1?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.5.7+dfsg-2ubuntu0.18.04.1"}]}],"versions":["4.5.7+dfsg-2"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"ckeditor","binary_version":"4.5.7+dfsg-2ubuntu0.18.04.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-33829.json"}},{"package":{"name":"ckeditor","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/ckeditor@4.12.1+dfsg-1ubuntu0.1?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.12.1+dfsg-1ubuntu0.1"}]}],"versions":["4.11.1+dfsg-1","4.12.1+dfsg-1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"ckeditor","binary_version":"4.12.1+dfsg-1ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-33829.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}