Published: 03 September 2008
The sbni_ioctl function in drivers/net/wan/sbni.c in the wan subsystem in the Linux kernel 220.127.116.11 does not check for the CAP_NET_ADMIN capability before processing a (1) SIOCDEVRESINSTATS, (2) SIOCDEVSHWSTATE, (3) SIOCDEVENSLAVE, or (4) SIOCDEVEMANSIPATE ioctl request, which allows local users to bypass intended capability restrictions.
From the Ubuntu security team
It was discovered that the SBNI WAN driver did not correctly check for the NET_ADMIN capability. A malicious local root user lacking CAP_NET_ADMIN would be able to change the WAN device configuration, leading to a denial of service.