This issue exists to document that a security improvement in the way that Jira Server and Data Center use templates has been implemented. Affected versions of Atlassian Jira Server and Data Center allowed remote attackers with system administrator permissions to execute arbitrary code via Template Injection leading to Remote Code Execution (RCE) in the Email Templates feature. In this case the security improvement was to protect against using the XStream library to be able to execute arbitrary code in velocity templates. The affected versions are before version 8.13.19, from version 8.14.0 before 8.20.7, and from version 8.21.0 before 8.22.1.