The krb5_gss_process_context_token function in lib/gssapi/krb5/process_context_token.c in the libgssapi_krb5 library in MIT Kerberos 5 (aka krb5) through 1.11.5, 1.12.x through 1.12.2, and 1.13.x before 1.13.1 does not properly maintain security-context handles, which allows remote authenticated users to cause a denial of service (use-after-free and double free, and daemon crash) or possibly execute arbitrary code via crafted GSSAPI traffic, as demonstrated by traffic to kadmind.

plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c in MIT Kerberos 5 (aka krb5) 1.12.x and 1.13.x before 1.13.1, when the KDC uses LDAP, allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) by creating a database entry for a keyless principal, as demonstrated by a kadmin "add_principal -nokey" or "purgekeys -all" command.

The krb5_ldap_get_password_policy_from_dn function in plugins/kdb/ldap/libkdb_ldap/ldap_pwd_policy.c in MIT Kerberos 5 (aka krb5) before 1.13.1, when the KDC uses LDAP, allows remote authenticated users to cause a denial of service (daemon crash) via a successful LDAP query with no results, as demonstrated by using an incorrect object type for a password policy.

The kadm5_randkey_principal_3 function in lib/kadm5/srv/svr_principal.c in kadmind in MIT Kerberos 5 (aka krb5) before 1.13 sends old keys in a response to a -randkey -keepold request, which allows remote authenticated users to forge tickets by leveraging administrative access.