Pope Benedict XVI is aware of it.
Indeed, the Acts and the Gospel of Thomas, both apocryphal works but in any case important for the study of Christian origins, were written in his name.
Gnosticism has been heretical since time immemorial. The problem with it is that there should be no special knowledge, no mud people, and a priesthood of all believers that is absent with gnosticism and its emphasis on special knowledge and deeper circles of revelation.
But, like the Pope said, it could be an interesting read. But it is
which means, take it with a grain of salt.
and to quote another footnote I found on the vatican's website with my frenimie Google's site search:
In fact, despite his lyrical language, St Irenaeus adopts and confirms a very rigid concept of the tetramorphous Gospel (“neither more than four, nor less than four, and only these four”), denying for all time any ecclesiastical value to any other gospels which existed in his day (regardless of their literary qualities), e.g. the Gospel of Peter, which was used by certain churches in the region of Antioch around 170 ... or the Gnostic Gospel of Thomas. The voice of St Irenaeus is a strong call to reject without hesitation the proposals to “reformulate” the canon of the New Testament, and in particular that of the Gospels, which, alas, have been recurring in recent years.
So all the way back to St. Irenaeus we've got a standard of "four and no more".
I believe one of those documents, has an interesting depiction of the Assumption (or Dormition) of Mary, which is good evidence of the historicity of the Tradition, but not referenced by any teachings as direct evidence for the doctrine.