Revision Note: V1.0 (January 12, 2016): Advisory published.
Summary: Microsoft is announcing the availability of an update to improve interoperability between Schannel-based TLS clients and 3rd-party TLS servers that enable RFC5077-based resumption and that send the NewSessionTicket message in the abbreviated TLS handshake. The update addresses an issue in schannel.dll that could cause RFC5077 session ticket-based resumption to fail and subsequently cause WinInet-based clients (for example, Internet Explorer and Microsoft Edge) to perform a fallback to a lower TLS protocol version than the one that would have been negotiated otherwise. This improvement is part of ongoing efforts to bolster the effectiveness of encryption in Windows.