Multiple buffer overflows in the (1) read and (2) write handlers in the Omnikey CardMan 4040 driver in the Linux kernel before 2.6.21-rc3 allow local users to gain privileges.
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.