krb5_ktkdb_get_entry() in lib/kdb/keytab.c in MIT Kerberos 5 (aka krb5) 1.2.8 and later does not free decrypted key material when a post-decryption check fails, which allows remote attackers to cause a denial of service (memory leak in the KDC or kadmind) via requests that repeatedly trigger key decryption failures.