The host is installed with Atlassian Confluence Server before 7.4.17, 7.5.0 before 7.13.7, 7.14.0 before 7.14.3, 7.15.0 before 7.15.2, 7.16.0 before 7.16.4, 7.17.0 before 7.17.4 or 7.18.0 and is prone to a servlet filter bypass vulnerability. A flaw is present in the application which fails to properly handle servlet filter. Successful exploitation allows unauthenticated attackers to casue cross-origin resource sharing