NSA was not aware of the recently identified vulnerability in OpenSSL, the so-called Heartbleed vulnerability, until it was made public in a private sector cybersecurity report
Or perhaps the "private sector cybersecurity report" was a IRC chat two years ago for l33t haxors.
They went on to: "Reports that NSA or any other part of the government were aware of the so-called Heartbleed vulnerability before April 2014 are wrong." so there's no weasel-wording going on here.
Perhaps they're using the etymological root of aware, which is "wary", and they mean they were unconcerned with its existence as they were unwary/unaware of any possible dangers with it since it was unknown to hostile forces.
Or perhaps the "private sector cybersecurity report" was a IRC chat two years ago for l33t haxors.