There is a cross-site-request forgery vulnerability in Esri Portal for ArcGIS Versions 11.1 and below that may in some cases allow a remote, unauthenticated attacker to trick an authorized user into executing unwanted actions via a crafted form. The impact to Confidentiality and Integrity vectors is limited and of low severity.
Workaround:
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.