The XPath functionality in unspecified web applications in Siemens WinCC 7.0 SP3 before Update 2 does not properly handle special characters in parameters, which allows remote authenticated users to read or modify settings via a crafted URL, related to an "XML injection" attack.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2012-2582
http://www.us-cert.gov/control_systems/pdf/ICSA-12-158-01.pdf