CKEditor, a third-party JavaScript library included in Drupal core, has [fixed a cross-site scripting (XSS) vulnerability](https://ckeditor.com/blog/CKEditor-4.9.2-with-a-security-patch-released/). The vulnerability stemmed from the fact that it was possible to execute XSS inside CKEditor when using the `image2` plugin (which Drupal 8 core also uses).
We would like to thank the CKEditor team for patching the vulnerability and coordinating the fix and release process, and matching the Drupal core security window.