Advisory Weakness Curation

CKEditor4 Cross-site Scripting vulnerability caused by incorrect CDATA detection ### Affected packages The vulnerability has been discovered in the core HTML parsing module and may affect all editor instances that: * Enabled full-page editing https://ckeditor.com/docs/ckeditor4/latest/features/fullpage.html mode, * or enabled CDATA https://ckeditor.com/docs/ckeditor4/latest/api/CKEDITOR_dtd.html#property-S-cdata elements in Advanced Content Filtering https://ckeditor.com/docs/ckeditor4/latest/guide/dev_advanced_content_filter.html 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 [security@cksource.com](mailto:security@cksource.com) if you have any questions or comments about this advisory. ### Acknowledgements The CKEditor 4 team would like to thank Michal Frýba https://cz.linkedin.com/in/michal-fryba from ALEF NULA https://www.alefnula.com/ for recognizing and reporting this vulnerability.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. A cross-site scripting vulnerability has been discovered in the core HTML parsing module in versions of CKEditor4 prior to 4.24.0-lts. It 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). The vulnerability allows attackers 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. A fix is available in version 4.24.0-lts.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. A cross-site scripting vulnerability has been discovered in the core HTML parsing module in versions of CKEditor4 prior to 4.24.0-lts. It 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). The vulnerability allows attackers 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. A fix is available in version 4.24.0-lts.