EAP 7 raises exception "Connection terminated parsing multipart data"

Issue

• We have a Web Application Firewall (WAF) that intercepts all HTTP requests, removes the body, and sends them to an application running on EAP 7 for authentication. For some reason multipart requests are failing with exception:

  58171 2019/02/07-08:10:04  Caused by: java.io.IOException: UT000036: Connection terminated parsing multipart data …  at io.undertow.server.handlers.form.MultiPartParserDefinition$MultiPartUploadHandler.parseBlocking(MultiPartParserDefinition.java:218)
  158173 2019/02/07-08:10:04      at io.undertow.servlet.spec.HttpServletRequestImpl.parseFormData(HttpServletRequestImpl.java:777)
  158174 2019/02/07-08:10:04      ... 50 more
  

  The security application ran before on EAP 6 and didn't raise such errors.