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.
The ConfluenceResourceDownloadRewriteRule class in Confluence Server and Confluence Data Center before version 6.13.18, from 6.14.0 before 7.4.6, and from 7.5.0 before 7.8.3 allowed unauthenticated remote attackers to read arbitrary files within WEB-INF and META-INF directories via an incorrect path access check.