{"cve":"CVE-2021-33829","nvd":{"published":"2021-06-09T12:15:07.863","modified":"2026-06-17T03:55:16.897","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://ckeditor.com/blog/ckeditor-4.16.1-with-accessibility-enhancements/#improvements-for-comments-in-html-parser","https://lists.debian.org/debian-lts-announce/2021/11/msg00007.html","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NYA354LJP47KCVJMTUO77ZCX3ZK42G3T/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UVOYN2WKDPLKCNILIGEZM236ABQASLGW/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WAGNWHFIQAVCP537KFFS2A2GDG66J7XD/"],"products":["ckeditor:ckeditor","debian:debian_linux","drupal:drupal","fedoraproject:fedora"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-33829","score":0.03189,"percentile":0.88088,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-rgx6-rjj4-c388","url":"https://osv.dev/vulnerability/GHSA-rgx6-rjj4-c388","summary":"ckeditor4 vulnerable to cross-site scripting","modified":"2025-12-10T23:41:06.105880Z","packages":[{"ecosystem":"npm","name":"ckeditor4","purl":"pkg:npm/ckeditor4","ranges":[">=4.14.0 <4.16.1"],"fixed":["4.16.1"]},{"ecosystem":"Packagist","name":"drupal/core","purl":"pkg:composer/drupal/core","ranges":[">=7.0.0 <7.80"],"fixed":["7.80"]},{"ecosystem":"Packagist","name":"drupal/core","purl":"pkg:composer/drupal/core","ranges":[">=8.0.0 <8.9.16"],"fixed":["8.9.16"]},{"ecosystem":"Packagist","name":"drupal/core","purl":"pkg:composer/drupal/core","ranges":[">=9.0.0 <9.0.14"],"fixed":["9.0.14"]},{"ecosystem":"Packagist","name":"drupal/core","purl":"pkg:composer/drupal/core","ranges":[">=9.1.0 <9.1.9"],"fixed":["9.1.9"]},{"ecosystem":"Packagist","name":"drupal/drupal","purl":"pkg:composer/drupal/drupal","ranges":[">=7.0.0 <7.80"],"fixed":["7.80"]},{"ecosystem":"Packagist","name":"drupal/drupal","purl":"pkg:composer/drupal/drupal","ranges":[">=8.0.0 <8.9.16"],"fixed":["8.9.16"]},{"ecosystem":"Packagist","name":"drupal/drupal","purl":"pkg:composer/drupal/drupal","ranges":[">=9.0.0 <9.0.14"],"fixed":["9.0.14"]},{"ecosystem":"Packagist","name":"drupal/drupal","purl":"pkg:composer/drupal/drupal","ranges":[">=9.1.0 <9.1.9"],"fixed":["9.1.9"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}