Joss is married to David Sackler, whose family owns Purdue Pharma, the makers of OxyContin, a drug critics claim has played a major role in America's opioid epidemic.
Courtney has trashed the heiress and her family, after turning down a $100,000 (£80,000) offer to attend her fashion show, and took issue with Patricia's decision to tote a bag designed by the wannabe fashion mogul, to the U.S. TV awards bash.
The "Hole" singer called out Patricia's stylist Annabelle Harron and her PR team in a series of posts on Instagram, calling on the "Boyhood" actress to "fire" whoever chose the silver bag.
Accusing them of taking money from the heiress, she wrote: "Ugh . So sad. Wiping out the values of a great woman with one sneaky a**ed bunch of money to @tukeconsulting @annabelleharron etc or influence peddling, or whatever it was. Disgusting."
Patricia and her team are yet to comment on the "Celebrity Skin" hitmaker's accusations.
The feud between Courtney and Joss began earlier this month, when Kurt Cobain's widow, who like her late husband struggled with drug addiction, announced she had turned down a $100,000 fee to attend the heiress' fashion show.