The poll also found:
* State Treasurer Rob McCord leads Corbett 42-39 percent.
* Former state Environmental Protection Secretary Katie McGinty and former state Revenue Secretary Tom Wolf each lead Corbett 44-37 percent.
* Allentown Mayor Ed Pawlowski leads Corbett 41-39 percent.
* Corbett leads just one Democrat, former state Environmental Protection Secretary John Hanger, 42-37 percent.
"Pennsylvania voters deliver a big bag of coal to Gov. Tom Corbett and directions to the State House exit as he heads into the holidays with the worst net approval rating he has ever had," Tim Malloy said in a news release with the poll. Malloy is assistant director of the Quinnipiac University Polling Institute.
Corbett's campaign quickly shrugged off the bad numbers.
"This race will be a marathon, not a sprint," Corbett campaign manager Mike Barley said. "Gov. Corbett is well within striking distance of his opponents, who are still struggling with very low name ID."
Jim Burn, chairman of the state Democratic Party, used the poll to knock Corbett on education funding and job creation.
"Tom Corbett's record has assured that Pennsylvanians will elect a Democratic governor in 2014," Burn said.
The pollsters also asked voters about their thoughts on gambling. They found a mixed bag: 55 percent said the state's casinos were a good thing, but 57 didn't want one in their town or city.
They also oppose legalizing online gambling 62-33 percent. Seventy percent said such a move would increase gambling addiction in the state.