Affected versions of Atlassian Confluence Server and Data Center allow users with a valid account on a Confluence Data Center instance to execute arbitrary Java code or run arbitrary system commands by injecting an OGNL payload. The affected versions are before version 6.13.23, from version 6.14.0 before 7.4.11, from version 7.5.0 before 7.11.6, and from version 7.12.0 before 7.12.5.