Several security vulnerabilities affecting ISC dhcpd, a server for automatic IP address assignment, have been discovered. Additionally, the latest security update for isc-dhcp, DSA-2516-1, did not properly apply the patches for CVE-2012-3571 and CVE-2012-3954. This has been addressed in this additional update. CVE-2011-4539 BlueCat Networks discovered that it is possible to crash DHCP servers configured to evaluate requests with regular expressions via crafted DHCP request packets. CVE-2012-3571 Markus Hietava of the Codenomicon CROSS project discovered that it is possible to force the server to enter an infinite loop via messages with malformed client identifiers. CVE-2012-3954 Glen Eustace discovered that DHCP servers running in DHCPv6 mode and possibly DHCPv4 mode suffer of memory leaks while processing messages. An attacker can use this flaw to exhaust resources and perform denial of service attacks.