Log Message:
dovecot2: updated to 2.3.5.2

v2.3.5.2
* CVE-2019-10691: Trying to login with 8bit username containing
  invalid UTF8 input causes auth process to crash if auth policy is
  enabled. This could be used rather easily to cause a DoS. Similar
  crash also happens during mail delivery when using invalid UTF8 in
  From or Subject header when OX push notification driver is used.