Security researcher Karthikeyan Bhargavan reported an issue
in Network Security Services (NSS) where MD5 signatures in the server signature within the
TLS 1.2 ServerKeyExchange message are still accepted. This is an issue since NSS has
officially disallowed the accepting MD5 as a hash algorithm in signatures since 2011. This
issues exposes NSS based clients such as Firefox to theoretical collision-based forgery
attacks. This issue was fixed in NSS version 3.20.2.