Fix buffer overflow, report and patch by Eugene C. (#4669)

code/qcommon/msg.c

@@ -1043,6 +1043,10 @@ void MSG_ReadDeltaEntity( msg_t *msg, entityState_t *from, entityState_t *to,
 	numFields = sizeof(entityStateFields)/sizeof(entityStateFields[0]);
 	lc = MSG_ReadByte(msg);
 
+	if ( lc > numFields || lc < 0 ) {
+		Com_Error( ERR_DROP, "invalid entityState field count" );
+	}
+
 	// shownet 2/3 will interleave with other printed info, -1 will
 	// just print the delta records`
 	if ( cl_shownet->integer >= 2 || cl_shownet->integer == -1 ) {
@@ -1376,6 +1380,10 @@ void MSG_ReadDeltaPlayerstate (msg_t *msg, playerState_t *from, playerState_t *t
 	numFields = sizeof( playerStateFields ) / sizeof( playerStateFields[0] );
 	lc = MSG_ReadByte(msg);
 
+	if ( lc > numFields || lc < 0 ) {
+		Com_Error( ERR_DROP, "invalid playerState field count" );
+	}
+
 	for ( i = 0, field = playerStateFields ; i < lc ; i++, field++ ) {
 		fromF = (int *)( (byte *)from + field->offset );
 		toF = (int *)( (byte *)to + field->offset );