Cross-site scripting (XSS) vulnerability in Redmine before 2.6.2 allows remote attackers to inject arbitrary web script or HTML via vectors involving flash message rendering.
https://www.redmine.org/projects/redmine/repository/entry/tags/2.6.2/doc/CHANGELOG
https://www.redmine.org/issues/19117
http://www.redmine.org/projects/redmine/wiki/Security_Advisories