In a wildcard certificate, the wildcard character should not be embedded within the U-label of an internationalized domain name. This was not properly implemented in NSS, as a result it did not handle IDNA domain prefixes according to RFC 6125, section 6.4.3 "Checking of Wildcard Certificates". http://tools.ietf.org/html/rfc6125#section-6.4.3
Upstream patch: https://hg.mozilla.org/projects/nss/rev/15ea62260c21 https://hg.mozilla.org/projects/nss/rev/2ffa40a3ff55 https://hg.mozilla.org/projects/nss/rev/709d4e597979
Upstream bug (not public): https://bugzilla.mozilla.org/showbug.cgi?id=903885
This issue was fixed upstream in NSS 3.16: https://developer.mozilla.org/en-US/docs/NSS/NSS3.16releasenotes