java.lang.NumberFormatException when extracting X-Forwarded-Port in ProxyPeerAddressHandler

The X-Forwarded-Port is set to a non-number which could mean the default HTTP port

ERROR [io.undertow.request] (default I/O-3) UT005071: Undertow request failed HttpServerExchange{ GET / request

{accept=[*/*], accept-language=[en, *;q=0.7], user-agent=[com.apple.WebKit.WebContent/11601.5.17.1 CFNetwork/760.4.2 Darwin/15.4.0 (x86_64)], connection=[Keep-Alive], X-Forwarded-Proto=[http], X-Forwarded-Port=[undefined], X-Forwarded-For=[199.19.249.196], X-Client-IP=[199.19.249.196], host=[blast-company77.rhcloud.com], X-Forwarded-Host=[blast-company77.rhcloud.com]}

response {}}: java.lang.NumberFormatException: For input string: "undefined"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at io.undertow.server.handlers.ProxyPeerAddressHandler.handleRequest(ProxyPeerAddressHandler.java:78)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.protocol.http.HttpReadListener.handleEventWithNoRunningRequest(HttpReadListener.java:232)
at io.undertow.server.protocol.http.HttpReadListener.handleEvent(HttpReadListener.java:130)
at io.undertow.server.protocol.http.HttpReadListener.handleEvent(HttpReadListener.java:56)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66)
at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:88)
at org.xnio.nio.WorkerThread.run(WorkerThread.java:559)