It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted URL-like text into the editor, and then press Enter or Space (in the Autolink plugin).
{ "binaries": [ { "binary_name": "ckeditor", "binary_version": "4.5.7+dfsg-2ubuntu0.16.04.1~esm2" } ] }
{ "binaries": [ { "binary_name": "ckeditor", "binary_version": "4.5.7+dfsg-2ubuntu0.18.04.1+esm1" } ] }
{ "binaries": [ { "binary_name": "ckeditor", "binary_version": "4.12.1+dfsg-1ubuntu0.1+esm1" } ] }