The merge_authdata function in kdc_authdata.c in the Key Distribution
Center (KDC) in MIT Kerberos 5 (aka krb5) 1.8.x before 1.8.4 does not
properly manage an index into an authorization-data list, which allows
remote attackers to cause a denial of service (daemon crash), or possibly
obtain sensitive information, spoof authorization, or execute arbitrary
code, via a TGS request that triggers an uninitialized pointer dereference,
as demonstrated by a request from a Windows Active Directory client.