OpenBSD 4.2 allows local users to cause a denial of service (kernel panic) by calling the SIOCGIFRTLABEL IOCTL on an interface that does not have a route label, which triggers a NULL pointer dereference when the return value from the rtlabel_id2name function is not checked.

Stack-based buffer overflow in the cons_options function in options.c in dhcpd in OpenBSD 4.0 through 4.2, and some other dhcpd implementations based on ISC dhcp-2, allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a DHCP request specifying a maximum message size smaller than the minimum IP MTU.