scumbag "condom," by 1967, slang, from scum + bag. Meaning "despicable person" is attested by 1971.

Etymonline

I found a condom reference back to 1939 in this snippet from the American Journal of Orthopsychiatry, Volume 9. The date seems accurate:

And I found this figurative use of the phrase from Chandler Brossard's 1953 The Bold Saboteurs:

What a scum bag of a world it was, what a miserable rat's life. I was getting so depressed I was forgetting the money in my pocket. In the early evening we all broke up. I told the fellows I might see them later at Sinbad's Bar

(See @Kit's comment above for current usage.)