Off-by-one error in the krb5_encode_krbsecretkey function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c in the LDAP KDB module in kadmind in MIT Kerberos 5 (aka krb5) 1.6.x through 1.11.x before 1.11.6 and 1.12.x before 1.12.2 allows remote authenticated users to cause a denial of service (buffer overflow) or possibly execute arbitrary code via a series of "cpw -keepold" commands.