NEW YORK — Through decades of digging into the private lives of rock stars and providing a forum for colorful writers like Hunter S. Thompson and P.J. O’Rourke, Rolling Stone magazine publisher Jann Wenner has never been afraid to push boundaries.

Now Wenner, who founded the magazine as a 20-year-old college dropout, is weathering the stiffest test of Rolling Stone’s credibility that the magazine has faced in its 48-year history.

On Sunday, the magazine retracted last November’s story on sexual assault at the University of Virginia in advance of the release of a damning Columbia University report about its reporting and editing, and on Monday, a fraternity named in the story threatened a lawsuit.

The magazine also faced criticism Monday for what some critics deemed a muted response to the problems outlined in Columbia’s exhaustive report.

The sharply funny O’Rourke, who worked at Rolling Stone from 1985 to 2000, said he found the editing and fact-checking there to be as rigorous as the legendarily tough New Yorker magazine.