Not sure what DHCP client you are running, but this may be of interest to you:
Somebody at OpenBSD discovered a possible root exploit in the ISC DHCP client. This exploit is present in all versions of the ISC DHCP client prior to 2.0pl1 and 3.0b1pl14, which was released on June 24th. Anybody who is using versions of the ISC DHCP client other than these are strongly urged to upgrade.
The ISC DHCP distribution is available at
ftp://ftp.isc.org/isc/DHCP,
and anonymous CVS at
http://www.isc.org/products/DHCP/anoncvs.html.
The head of the tree in anonymous CVS also contains the fix.