Common among - Rather, great (heavy) upon people.

There is an evil which I have seen under the sun,.... The Vulgate Latin version reads it, another evil; but wrongly, for the same is considered as before, the evil of covetousness; which is one of the evil things that come out of the heart of man; is abominable to the Lord, contrary to his nature and will, and a breach of his law, which forbids it, and is the root of all evil; this is an evil under the sun, for there is nothing of this kind above it; and it fell under the observation of Solomon in various instances;
and it is common among men; or, "great over men" (u); or "over the man", the covetous man: it spreads itself over them; few were free from it, even so long ago, in those early times, and in such times in which silver was made no account of, and was like stones in Jerusalem, as common as they; and yet the sin of covetousness, of hoarding up money and making no use of it, for a man's own good, and the good of others, was very rife among men, 1-Kings 10:27.
(u) "et multum ipsum super hominem", Montanus; "et magaum est illud super hominem istum", Rambachius.

A man often has all he needs for outward enjoyment; yet the Lord leaves him so to covetousness or evil dispositions, that he makes no good or comfortable use of what he has. By one means or other his possessions come to strangers; this is vanity, and an evil disease. A numerous family was a matter of fond desire and of high honour among the Hebrews; and long life is the desire of mankind in general. Even with these additions a man may not be able to enjoy his riches, family, and life. Such a man, in his passage through life, seems to have been born for no end or use. And he who has entered on life only for one moment, to quit it the next, has a preferable lot to him who has lived long, but only to suffer.

(Ecclesiastes 6:1-12)
common--or else more literally,--"great upon man," falls heavily upon man.

"There is an evil which I have seen under the sun, and in great weight it lies upon man: a man to whom God giveth riches, and treasures, and honour, and he wanteth nothing for his soul of all that he may wish, but God giveth him not power to have enjoyment of it, for a strange man hath the enjoyment: that is vanity and an evil disease." The author presents the result of personal observation; but inasmuch as he relates it in the second tense, he generalizes the matter, and places it scenically before the eyes of the reader. A similar introduction with ישׁ, but without the unnecessary asher, is found at Ecclesiastes 5:12; Ecclesiastes 10:5. Regarding בּה, vid., under Ecclesiastes 8:6; על does not denote the subj., as at Ecclesiastes 2:17 : it appears great to a man, but it has its nearest lying local meaning; it is a great (Ecclesiastes 2:21) evil, pressing in its greatness heavily upon man. The evil is not the man himself, but the condition in which he is placed, as when, e.g., the kingdom of heaven is compared to a merchant (Matthew 13:45.), - not the merchant in himself, but his conduct and life is a figure of the kingdom of heaven.