Schneider Electric Wonderware Information Server (WIS) Portal 4.0 SP1 through 5.5 allows remote attackers to read arbitrary files or cause a denial of service via an XML external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.
Credits
Timur Yunusov, Ilya Karpov, Sergey Gordeychik, Alexey Osipov, and Dmitry Serebryannikov of the Positive Technologies Research Team