Juan Please post you program so we can see what the issue is.
I can't send you my project as it is confidential, but I can send you an program that reproduce the same behavior, the base project is from cy.wbz (https://www.element14.com/community/thread/23868/l/psoc-4-pioneer-kit-community-project04-usb-uart-utility?displayFullThread=true)
I just added the line enabling the Pullup resitor.
Have a look in the main:
/* Start SCB UART TX+RX operation */
/* Transmit String through UART TX Line */
UART_UartPutString("PULLUP ON RX USB-UART");
USB-UART.Bundle01.zip 1.1 MB
Some more informations: beside the fact that the input is let open, the current drain goes up to + 500uA.