Eleventh-hour campaign mailings from the New York State Democratic Committee imply Cynthia Nixon is anti-Semitic — prompting an online maelstrom of outrage and denials Saturday night, with Gov. Cuomo and the state party calling the mailer a “mistake.”

“With anti-Semitism and bigotry on the rise, we can’t take a chance with inexperienced Cynthia Nixon,” reads the mailer, which says it was paid for by the New York State Democratic Committee.

It goes on to accuse Nixon of being against the funding of yeshivas — a topic she’s actually dodged — and falsely accuses her of being “silent on the rise of anti-Semitism” and of supporting the Boycott, Divestment, Sanctions (BDS) movement.

Teachers’ union head Randi Weingarten, and her wife, Rabbi Sharon Kleinbaum — whose LGBT-friendly synagogue, Congregation Beth Simhat Torah, on W. 30th Street, Nixon attends — issued a joint Facebook posting at 9 p.m. calling the mailing “beyond the pale.”

“How dare you, @nydems?!” tweeted NYC Council Member Brad Lander.

“Smearing @CynthiaNixon (whose kids are being raised Jewish, BTW) as soft on anti-Semitism & lying about her position on Israel in order to fearmonger and shill for votes is a shameful dead-end for our party,” he tweeted.

The New York-based progressive “The Jewish Vote” organization called the mailing “heinous,” and urged angry Nixon supporters to join the primary candidate for a pre-Rosh Hashanah meet-up Sunday at 5 p.m. at Zabars on Broadway and W. 80th St.

“This is a shameful smear, @nydems,” tweeted Abe Silberstein , who writes about Israeli politics for the Jerusalem Post, Haaretz and other publications.

Cuomo spokeswoman Lis Smith tweeted at 5:30 p.m. that the governor “didn’t approve of or have any knowledge of the mailer.”

Soon afterward, the committee’s executive director, Geoff Berman, tweeted that the mailer was “a mistake and is inappropriate.”

Their responses only fanned the online flames.

“Pretty convenient for the Governor to use the NYS Democratic Party to do the dirty work of his dog-whistle attack politics and then “condemn” it,” Lander later tweeted.

Nixon’s campaign had not responded to the smear as of Saturday night.