Amazon Linux AMI Security Advisory: ALAS-2018-1129
Advisory Release Date: 2019-01-25 02:39 Pacific
MIT krb5 1.6 or later allows an authenticated kadmin with permission to add principals to an LDAP Kerberos database to circumvent a DN containership check by supplying both a "linkdn" and "containerdn" database argument, or by supplying a DN string which is a left extension of a container DN string but is not hierarchically within the container DN. (CVE-2018-5730 )
MIT krb5 1.6 or later allows an authenticated kadmin with permission to add principals to an LDAP Kerberos database to cause a denial of service (NULL pointer dereference) or bypass a DN container check by supplying tagged data that is internal to the database module. (CVE-2018-5729 )
Run yum update krb5 to update your system.