CVE-2012-3725
The DNAv4 protocol implementation in the DHCP component in Apple iOS before 6 sends Wi-Fi packets containing a MAC address of a host on a previously used network, which might allow remote attackers to obtain sensitive information about previous device locations by sniffing an unencrypted Wi-Fi network for these packets.
Date published : 2012-09-20
http://lists.apple.com/archives/security-announce/2012/Sep/msg00003.html