do_tgs_req.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.11 before 1.11.4, when a single-component realm name is used, allows remote authenticated users to cause a denial of service (daemon crash) via a TGS-REQ request that triggers an attempted cross-realm referral for a host-based service principal.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.