Version 6.3 of UTS #39: Unicode Security Mechanisms has been released. Because the Unicode Standard contains such a large number of characters for the writing systems of the world, caution is necessary to avoid exposing programs and systems to possible security attacks. This document provides mechanisms for reducing the risk of problems, while the associated UTR #36: Unicode Security Considerations describes a variety of security considerations for Unicode and guidelines for dealing with them.
UTS #39 includes a new Restriction Level (Single Script), and a number of clarifications for confusable detection, restriction revels, and optional detection. It also contains a new section describing how the identifier data is generated. That identifier data has been expanded to include certain characters from UAX #31: Unicode Identifier and Pattern Syntax, a few extra characters allowed in IDNA2008 (Internationalized Domain Name Architecture, http://tools.ietf.org/html/rfc5890), and certain characters based on user feedback. The version numbering has also been changed to align with versions of the Unicode Standard.
The associated UTR #36 has some smaller changes. There are a few important corrections, and the addition of new sections discussing security issues with transitivity and idempotence. There are also a few related new FAQ entries on http://www.unicode.org/faq/security.html.