The OAuth status rest resource in Atlassian Application Links before version 5.2.7, from 5.3.0 before 5.3.4 and from 5.4.0 before 5.4.3 allows remote attackers with administrative rights to access the content of internal network resources via a Server Side Request Forgery (SSRF) by creating an OAuth application link to a location they control and then redirecting access from the linked location's OAuth status rest resource to an internal location. When running in an environment like Amazon EC2, this flaw maybe used to access to a metadata resource that provides access credentials and other potentially confidential information.