Issue 1634 - ABP for IE dev build v1.2.727 - ieframe crash

src/plugin/PluginWbPassThrough.cpp

 #include "PluginStdAfx.h"
 
 #include "PluginWbPassThrough.h"
 #include "PluginClient.h"
 #include "PluginClientFactory.h"
 #include "PluginFilter.h"
 #include "PluginSettings.h"
 #include "PluginClass.h"
 #include "PluginSystem.h"
 #include <WinInet.h>
@@ skipping 309 matching lines @@
         m_contentType = ContentType::CONTENT_TYPE_SUBDOCUMENT;
       }
     }
   }
 
   if (IsFlashRequest(pszAdditionalHeaders))
   {
     m_contentType = ContentType::CONTENT_TYPE_OBJECT_SUBREQUEST;
   }
 
-  if (pszAdditionalHeaders && IsXmlHttpRequest(*pszAdditionalHeaders))
+  if (pszAdditionalHeaders && *pszAdditionalHeaders && IsXmlHttpRequest(*pszAdditionalHeaders))
   {
     m_contentType = ContentType::CONTENT_TYPE_XMLHTTPREQUEST;
   }
 
   m_blockedInTransaction = client->ShouldBlock(szURL, m_contentType, m_boundDomain);
   if (m_blockedInTransaction)
   {
     return E_ABORT;
   }
   return nativeHr;
@@ skipping 45 matching lines @@
   }
 
   return OnStart(szUrl, pOIProtSink, pOIBindInfo, grfPI, dwReserved, m_spInternetProtocol);
 }
 
 STDMETHODIMP WBPassthru::Read(/* [in, out] */ void *pv,/* [in] */ ULONG cb,/* [out] */ ULONG *pcbRead)
 {
   WBPassthruSink* pSink = GetSink();
   return pSink->OnRead(pv, cb, pcbRead);
 }