"This has been a bad few months for journalism," Pelley said. "We're getting the big stories wrong over and over again."
The "CBS Evening News" anchor made the criticism while accepting a journalism award named for broadcast executive Fred Friendly from Quinnipiac University. He didn't exempt himself, noting that during early reporting of the Newtown, Conn., elementary school massacre last December he mistakenly reported that shooter Adam Lanza's mother was a teacher in the school.
Media organizations were roundly criticized for falsely reporting an arrest of a Boston Marathon bombing suspect two days after the April 15 attack. Stories and pictures spread quickly on social media websites erroneously suggesting some people on the scene were suspects, and the images were used by some news organizations.
"In a world where everybody is a publisher, no one is an editor," Pelley said, "and we've arrived at the point today."
Twitter, Facebook and Reddit are "not journalism," he said. "That's gossip. Journalism was invented as an antidote to gossip."
He repeated a maxim heard often in newsrooms recently: "If you're first, no one will ever remember. If you're wrong, no one will ever forget."
The race to be first on stories is "vanity," he said. "It's self-conceit. We do it to make ourselves feel better."
Media critic Howard Kurtz apologized this week on his CNN show, "Reliable Sources," for messing up a story about NBA player Jason Collins and was sharply criticized by other media critics on the air.
Kurtz had written that Collins, who made headlines by being the first active player in one of the four major U.S. pro sports leagues to come out as gay, had hidden a previous engagement to a woman in his announcement. In fact, Collins revealed the engagement in his first-person Sports Illustrated story and in a subsequent ABC interview.
Kurtz's story was published on The Daily Beast website, which subsequently parted ways with Kurtz in a decision he said was long in the works. Kurtz said the story was riddled with errors and shouldn't have been written in the first place.
CNN chief executive Jeff Zucker said on Friday that he was comfortable with Kurtz's apology and had no plans to replace him on the weekly media criticism show.