Format string vulnerability in Screen Sharing Server in Apple Mac OS X before 10.9 and Apple Remote Desktop before 3.5.4 allows remote attackers to execute arbitrary code via format string specifiers in a VNC username.

Apple Remote Desktop before 3.7 does not properly use server authentication-type information during decisions about whether to present an unencrypted-connection warning message, which allows remote attackers to obtain sensitive information in opportunistic circumstances by sniffing the network during an unintended cleartext VNC session.

Apple Remote Desktop before 3.6.1 does not recognize the "Encrypt all network data" setting during connections to third-party VNC servers, which allows remote attackers to obtain cleartext VNC session content by sniffing the network.