Deserialization of untrusted data in Kentico CMS allows remote attackers to execute arbitrary code.
An issue was discovered in Kentico before 12.0.15. Due to a failure to validate security headers, it was possible for a specially crafted request to the staging service to bypass the initial authentication and proceed to deserialize user-controlled .NET object input. This deserialization then led to unauthenticated remote code execution on the server where the Kentico instance was hosted.
Update your Kentico CMS to the latest version to eliminate this vulnerability.