krb5: Ignore password attributes for S4U2Self requests (CVE-2018-20217)
A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5
(aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket
an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.
(from redmine: issue id 9801, created on 2018-12-27, closed on 2019-01-09)