Gov. Andrew Cuomo is maintaining a double-digit lead over his Republican challenger, but he could be vulnerable to a challenge from the left, according to a poll of New York voters released Tuesday.

The Siena College poll shows the Democrat leading Westchester County Executive Rob Astorino 58 percent to 28 percent. Cuomo had a lead of 61 percent to Astorino’s 26 percent in Siena’s poll last month.

Astorino, who announced his candidacy last month, remains largely unknown, with 66 percent of polled voters either not knowing who he is or having no opinion of him with seven months left until the election.

If the race were to include a candidate from the left-leaning Working Families Party, Cuomo’s lead over Astorino is cut by about 20 points, with 39 percent of polled voters favoring Cuomo and 24 percent each for Astorino and the unnamed WFP candidate.

The percentage of voters who rated Cuomo’s job performance as excellent or good is up by two points to 48 percent.

The poll also found that voters are lukewarm about Cuomo’s test program to let 20 hospitals statewide provide medical marijuana to seriously ill patients. Siena reports that 26 percent of voters said they prefer the governor’s program while 51 percent — the highest number recorded in polling so far — support legalizing medical marijuana and 21 percent want to keep it illegal.

Amid controversy surrounding Cuomo’s decision to shut down the special Moreland Commission to investigate public corruption, less than a third of voters has been following the issue and only one-quarter has heard or read about the shutdown, although 84 percent of voters say corruption in Albany is a serious problem.

Meanwhile, 61 percent of voters agree with a federal prosecutor who said the Moreland Commission should have continued to investigate state government corruption. Cuomo has said a new ethics law negotiated with the Legislature justified disbanding the commission.

The telephone poll of 772 registered voters was conducted April 12 to 17. It has a margin of error of plus or minus 3.5 percentage points.

(AP)