The isdn_ioctl function in isdn_common.c in Linux kernel 2.6.23 allows local users to cause a denial of service via a crafted ioctl struct in which iocts is not null terminated, which triggers a buffer overflow.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.