Microsoft SQL Server 'Malformed TDS Packet Header' Vulnerability patch - Version 1 If a specially-malformed TDS packet is sent to a SQL server, it can cause the SQL service to crash. This vulnerability would not allow any inappropriate access to the data on the server, nor would it allow a malicious user to usurp any administrative control on the machine. An affected machine could be put back into service by restarting the SQL service. This vulnerability could only be remotely exploited if port 1433 were open at the firewall.