Jira Data Center, Jira Core Data Center, Jira Software Data Center from version 6.3.0 before 8.5.16, from 8.6.0 before 8.13.8, from 8.14.0 before 8.17.0 and Jira Service Management Data Center from version 2.0.2 before 4.5.16, from version 4.6.0 before 4.13.8, and from version 4.14.0 before 4.17.0 exposed a Ehcache RMI network service which attackers, who can connect to the service, on port 40001 and potentially 40011[0][1], could execute arbitrary code of their choice in Jira through deserialization due to a missing authentication vulnerability. While Atlassian strongly suggests restricting access to the Ehcache ports to only Data Center instances, fixed versions of Jira will now require a shared secret in order to allow access to the Ehcache service. [0] In Jira Data Center, Jira Core Data Center, and Jira Software Data Center versions prior to 7.13.1, the Ehcache object port can be randomly allocated. [1] In Jira Service Management Data Center versions prior to 3.16.1, the Ehcache object port can be randomly allocated.