The vty layer in Quagga before 0.96.4, and Zebra 0.93b and earlier, does not verify that sub-negotiation is taking place when processing the SE marker, which allows remote attackers to cause a denial of service (crash) via a malformed telnet command to the telnet CLI port, which may trigger a null dereference.

The getifaddrs function in GNU libc (glibc) 2.2.4 and earlier allows local users to cause a denial of service by sending spoofed messages as other users to the kernel netlink interface.