title: Subdomain cookie sharing in nginx
body: <p>I have server, running some number of sites.
  For example: example.com a.example.com b.example.com
  All sites are routed via nginx to unix domain-sockets.
  Each of sites is gunicorn instance.</p>
  
  <p>Can applications from subdomains read/write cookie data from example.com or from other subdomains?
  If yes, how to disable it?</p>