clnttcp_call() in lib/rpc/clnt_tcp.c in MIT Kerberos 5 (aka krb5) does not free the RPC reply verifier between retries, which allows remote attackers to cause a denial of service (memory leak in GSS-RPC client programs) by injecting RPC replies with mismatched XIDs or by triggering authentication retries.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.