source: https://www.securityfocus.com/bid/42025/info

Jira is prone to multiple cross-site scripting vulnerabilities and an information disclosure vulnerability because the application fails to sufficiently sanitize user-supplied input.

Attackers can exploit these issues to obtain sensitive information, steal cookie-based authentication information, and execute arbitrary client-side scripts in the context of the browser.

Jira 4.01 is vulnerable; other versions may also be affected.

http://www.example.com/ViewIssue.jspa?id=[VALID_ID]&watch=true&returnUrl=data:text/html,<script>alert(0)</script>
http://www.example.com/AttachFile!default.jspa?id=[VALID_ID]&returnUrl=javascript:alert(0)';foo='