Application Links before version 5.0.11, from version 5.1.0 before 5.2.10, from version 5.3.0 before 5.3.6, from version 5.4.0 before 5.4.12, and from version 6.0.0 before 6.0.4 allows remote attackers to inject arbitrary HTML or JavaScript via a cross site scripting (XSS) vulnerability in the applinkStartingUrl parameter. The product is used as a plugin in various Atlassian products where the following are affected: Confluence before version 6.15.2, Crucible before version 4.7.0, Crowd before version 3.4.3, Fisheye before version 4.7.0, Jira before version 7.13.3 and 8.x before 8.1.0.

The ListEntityLinksServlet resource in Application Links before version 5.0.12, from version 5.1.0 before version 5.2.11, from version 5.3.0 before version 5.3.7, from version 5.4.0 before 5.4.13, and from version 6.0.0 before 6.0.5 disclosed application link information to non-admin users via a missing permissions check.

The EditApplinkServlet resource in the Atlassian Application Links plugin before version 5.4.20, from version 6.0.0 before version 6.0.12, from version 6.1.0 before version 6.1.2, from version 7.0.0 before version 7.0.1, and from version 7.1.0 before version 7.1.3 allows remote attackers who have obtained access to administrator's session to access the EditApplinkServlet resource without needing to re-authenticate to pass "WebSudo" in products that support "WebSudo" through an improper access control vulnerability.