Zebra 0.93b and earlier, and quagga before 0.95, allows local users to cause a denial of service by sending spoofed messages as other users to the kernel netlink interface.
http://secunia.com/advisories/10563
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10169
http://www.debian.org/security/2004/dsa-415
http://www.redhat.com/support/errata/RHSA-2003-305.html