--- vnc-4_1_1-unixsrc/common/rfb/SConnection.cxx.authentication	2005-03-11 16:08:41.000000000 +0100
+++ vnc-4_1_1-unixsrc/common/rfb/SConnection.cxx	2006-05-17 16:15:54.000000000 +0200
@@ -181,6 +181,15 @@
   vlog.info("Client requests security type %s(%d)",
             secTypeName(secType),secType);
 
+     // Verify that the requested security type should be offered
+   std::list<rdr::U8> secTypes;
+   std::list<rdr::U8>::iterator i;
+   securityFactory->getSecTypes(&secTypes, reverseConnection);
+   for (i=secTypes.begin(); i!=secTypes.end(); i++)
+     if (*i == secType) break;
+   if (i == secTypes.end())
+     throw Exception("Requested security type not available");
+
   try {
     state_ = RFBSTATE_SECURITY;
     security = securityFactory->getSSecurity(secType, reverseConnection);