I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. I apologize for being very late with this review and since this is already in the IESG process it is clearly ok to completely ignore this review! In summary I think the security considerations sections have a few issues. In particular several of the identified security issues in section 10 of RFC 6455 place requirements on implementations and profiles but JMAP websocket makes no effort to expand on those requirements. For instance is the intention of jmap websocket to be built into non- browser clients so section 10.1 applies (or not)? What are the authentication requirements of jmap websocket (section 10.5) etc. I think the security considerations should make an attempt to cover this if at all possible.