export DISPLAY does not work after last security update

Hi everybody,

I have a linux box that I use by ssh connection. For all the X11 staff, I was exporting the DISPLAY to my Mac's X11 server, and then use them (after using xhost + command on my Mac of course).

It has been working until today. What I do:

Open X11, then launch xterm. then:
xhost +
ssh -X hostname
export DISPLAY=my macsip:0

then launch X programs and DISPLAY them locally.

Can you please help? (I think that it is related with the latest security update)

Any ideas?

Thanks in advance...