diff --git a/src/libosmo-mgcp-client/mgcp_client.c b/src/libosmo-mgcp-client/mgcp_client.c
index 910289e..3f8e780 100644
--- a/src/libosmo-mgcp-client/mgcp_client.c
+++ b/src/libosmo-mgcp-client/mgcp_client.c
@@ -268,7 +268,7 @@
 {
 	char *pt_str;
 	char *pt_end;
-	unsigned int pt;
+	unsigned long int pt;
 	unsigned int count = 0;
 	unsigned int i;
 
@@ -298,6 +298,9 @@
 		    pt_str == pt_end)
 			goto response_parse_failure_pt;
 
+		if (pt >> 7) /* PT is 7 bit field, higher values not allowed */
+			goto response_parse_failure_pt;
+
 		/* Do not allow duplicate payload types */
 		for (i = 0; i < count; i++)
 			if (r->codecs[i] == pt)