Buffer overflow in the RPC library (lib/rpc/rpc_dtablesize.c) used by libgssrpc and kadmind in MIT Kerberos 5 (krb5) 1.2.2, and probably other versions before 1.3, when running on systems whose unistd.h does not define the FD_SETSIZE macro, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code by triggering a large number of open file descriptors.
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.