Amazon Linux AMI Security Advisory: ALAS-2017-793
Advisory Release Date: 2017-02-06 18:00 Pacific
A NULL pointer dereference flaw was found in MIT Kerberos kadmind service. An authenticated attacker with permission to modify a principal entry could use this flaw to cause kadmind to dereference a null pointer and crash by supplying an empty DB argument to the modify_principal command, if kadmind was configured to use the LDAP KDB module. (CVE-2016-3119 )
A NULL pointer dereference flaw was found in MIT Kerberos krb5kdc service. An authenticated attacker could use this flaw to cause krb5kdc to dereference a null pointer and crash by making an S4U2Self request, if the restrict_anonymous_to_tgt option was set to true. (CVE-2016-3120 )
Run yum update krb5 to update your system.