A recent report that Apple would cut its sales forecast for the iPhone X appears to have "cast a shadow over everything," closely followed trader Art Cashin told CNBC on Wednesday.

He spoke a day after Apple posted its worst day since August. Taiwan's Economic Daily newspaper, citing unidentified sources, reported Tuesday that the tech giant would be slashing its sales forecast for the iPhone X in the quarter to 30 million units.

Apple's stock was modestly lower on Wednesday.

"The negative news surrounding Apple cast a shadow over everything. Most of the tax, the Apple suppliers, etc., etc.," Cashin said on "Squawk on the Street." "We'll see if they can shake that off and get started again here."

Regarding the overall market Wednesday, Cashin said it doesn't look "awe-inspiring."

"We're still waiting to see if the Santa Claus rally can get started," said Cashin, UBS' director of floor operations at the New York Stock Exchange.

On Tuesday, Cashin said President Donald Trump's signing of the tax overhaul would distort the holiday rally, which generally runs through the first two trading days of January.

"This has been a dreadful year for seasonal patterns. Almost none of them have worked," Cashin said.

"People didn't know how [the tax bill] was going to be treated," he added. "So that also may have thrown some other things off."