Sorry, I have to disagree

Sklo Union pieces have a ground and polished (slightly matte) base, whereas the vase in question seems to have a moulded base, which is common in Oberglas pieces (and not all Oberglas pieces have star-cut bases)
>> LinkBesides that, Sklo Union glass is quite well documented, so there should be a reference somewhere to be found...
IMHO, a vague similarity to some Zejmon designs is not enough for attribution, the Oberglas ashtray I linked to above is a far better match for the pattern.
This design is commonly seen here in Vienna, and I am sure I have seen it with an Oberglas label.
Michael