As a draft report prepared by CBS’s outside lawyers now makes clear, many of the company’s employees, including high-ranking executives and even members of its board, were aware of the former chief executive Leslie Moonves’s alleged sexual misconduct and subsequent efforts to conceal it.

Yet no one acted to stop him — and the repercussions for that failure are likely to reverberate at CBS for years.

“A culture where this behavior could have gone unchecked for so long with so much knowledge is really troubling,” said Charles M. Elson, an expert on corporate governance at the University of Delaware. “This is a disaster for CBS shareholders. There’s been no other #MeToo incident with this kind of negative impact” on a major American company.

One longtime CBS executive — the former communications director Gil Schwartz — drafted a letter of resignation for Mr. Moonves after becoming privy to one of the most serious allegations against him, according to the draft report, which was reviewed by The New York Times. Yet the letter was never sent, and Mr. Schwartz said nothing about it to board members.