CKEditor: Cross-site scripting (XSS) in the engine package

Summary

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. From 45.0.0 until 47.7.4 and 48.5.1, the engine uses a vulnerable es-toolkit version whose prototype-pollution behavior can be reached while CKEditor processes incoming style attribute values. Crafted editor content can thereby cause unauthorized JavaScript execution in the browser. This issue is fixed in versions 47.7.4 and 48.5.1.

Remediation

1. Inventory every ckeditor ckeditor5 deployment, including staging.
2. No fixed version appears in the public sources yet. Check the references below and the vendor directly.

References

• Referencehttps://github.com/ckeditor/ckeditor5/security/advisories/GHSA-rh54-vffm-5fvp
• Referencehttps://github.com/ckeditor/ckeditor5/commit/4d9c5bb34f63cd956d15ccafbe584e14280c86a0
• Referencehttps://github.com/ckeditor/ckeditor5/commit/a750e38635db6a18c5b11599c09f4fd702850423
• Referencehttps://github.com/ckeditor/ckeditor5/releases/tag/v47.7.4
• Referencehttps://github.com/ckeditor/ckeditor5/releases/tag/v48.5.1