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.
i686: krb5-devel-1.15.1-34.44.amzn1.i686 krb5-workstation-1.15.1-34.44.amzn1.i686 krb5-pkinit-openssl-1.15.1-34.44.amzn1.i686 krb5-server-1.15.1-34.44.amzn1.i686 krb5-server-ldap-1.15.1-34.44.amzn1.i686 libkadm5-1.15.1-34.44.amzn1.i686 krb5-libs-1.15.1-34.44.amzn1.i686 krb5-debuginfo-1.15.1-34.44.amzn1.i686 src: krb5-1.15.1-34.44.amzn1.src x86_64: krb5-server-ldap-1.15.1-34.44.amzn1.x86_64 krb5-devel-1.15.1-34.44.amzn1.x86_64 krb5-debuginfo-1.15.1-34.44.amzn1.x86_64 krb5-workstation-1.15.1-34.44.amzn1.x86_64 libkadm5-1.15.1-34.44.amzn1.x86_64 krb5-libs-1.15.1-34.44.amzn1.x86_64 krb5-server-1.15.1-34.44.amzn1.x86_64 krb5-pkinit-openssl-1.15.1-34.44.amzn1.x86_64