The attached test compares the values retrieved via CFFParser from an OpenType font with the expected values as seen in FontForge (go to Element->Font Info->PS Private).
The font NeoSans Black.otf can be found at https://www.wfonts.com/font/neosans
The CFF font specification explaining the encoding of the entries which are incorrectly parsed by FontBox CFFParser can be found here https://typekit.files.wordpress.com/2013/05/5176.cff.pdf
We use FontBox to read the font when we need to embed it into an PDF which we produce via our Apache FOP based software. Adobe validator complains about incorrect "Blue values" sorting then.