CKEditor is vulnerable to a denial of service, caused by a regular expression denial of service (ReDoS) flaw in the dialog plugin. By sending a specially-crafted regex input, a remote attacker could exploit this vulnerability to cause a significant performance drop and results in a browser tab freeze.

CKEditor is vulnerable to cross-site scripting, caused by improper validation of user-supplied input. A remote authenticated attacker could exploit this vulnerability to inject malicious script into a Web page which would be executed in a victim's Web browser within the security context of the hosting Web site, once the page is viewed. An attacker could use this vulnerability to steal the victim's cookie-based authentication credentials.