GHSA-fq6h-4g8v-qqvm CKEditor4 Cross-site Scripting vulnerability caused by incorrect CDATA detection

• npm ckeditor4: < 4.24.0-lts → fixed in 4.24.0-lts • Packagist ckeditor/ckeditor: < 4.24.0 → fixed in 4.24.0

Affected packages The vulnerability has been discovered in the core HTML parsing module and may affect all editor instances that: • Enabled full-page editing mode, • or enabled CDATA elements in Advanced Content Filtering configuration (defaults to `script` and `style` elements). Impact A potential vulnerability has been discovered in CKEditor 4 HTML processing core module. The vulnerability allowed to inject malformed HTML content bypassing Advanced Content Filtering mechanism, which could result in executing JavaScript code. An attacker could abuse faulty CDATA content detection and use it to prepare an intentional attack on the editor. It affects all users using the CKEditor 4 at version < 4.24.0-lts. Patches The problem has been recognized and patched. The fix will be available in version 4.24.0-lts. For more information Email us at [email protected] if you have any questions or comments about this advisory. Acknowledgements The CKEditor 4 team would like to thank Michal Frýba from ALEF NULA for recognizing and reporting this vulnerability.