diff --git a/src/mms/iso_cotp/cotp.c b/src/mms/iso_cotp/cotp.c
index f57e05bc..bec87729 100644
--- a/src/mms/iso_cotp/cotp.c
+++ b/src/mms/iso_cotp/cotp.c
@@ -466,9 +466,14 @@ parseOptions(CotpConnection* self, uint8_t* buffer, int bufLen)
             if (optionLen < 5) {
                 self->options.tSelDst.size = optionLen;
 
+                const uint8_t TransportSelectorConstValue[4] = {0,1,0,0};
                 int i;
                 for (i = 0; i < optionLen; i++)
+                {
                     self->options.tSelDst.value[i] = buffer[bufPos++];
+ 				   if(TransportSelectorConstValue[i] != self->options.tSelDst.value[i])
+ 					   return false;
+                }
             }
             else
                 goto cpo_error;
diff --git a/src/mms/iso_presentation/iso_presentation.c b/src/mms/iso_presentation/iso_presentation.c
index c4f2f64e..f54909ad 100644
--- a/src/mms/iso_presentation/iso_presentation.c
+++ b/src/mms/iso_presentation/iso_presentation.c
@@ -447,9 +447,14 @@ parseNormalModeParameters(IsoPresentation* self, uint8_t* buffer, int totalLengt
             }
             else {
                 self->calledPresentationSelector.size = len;
+                const uint8_t PresentationSelectorConstValue[16] = {0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0};
                 int i;
                 for (i = 0; i < len; i++)
+                {
                     self->calledPresentationSelector.value[i] = buffer[bufPos + i];
+ 				   if(PresentationSelectorConstValue[i] != self->calledPresentationSelector.value[i])
+ 					   return -1;
+                }
             }
 
             bufPos += len;
diff --git a/src/mms/iso_session/iso_session.c b/src/mms/iso_session/iso_session.c
index e41cbedd..c3486c7c 100644
--- a/src/mms/iso_session/iso_session.c
+++ b/src/mms/iso_session/iso_session.c
@@ -187,9 +187,14 @@ parseSessionHeaderParameters(IsoSession* session, ByteBuffer* message, int param
             {
                session->calledSessionSelector.size = parameterLength;
 
+               const uint8_t SessionSelectorConstValue[16] = {0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
                int i;
                for (i = 0; i < session->calledSessionSelector.size; i++)
+               {
                    session->calledSessionSelector.value[i] = message->buffer[offset++];
+				   if(SessionSelectorConstValue[i] != session->calledSessionSelector.value[i])
+					   return SESSION_ERROR;
+               }
             }
 
             break;