Democrat Ned Lamont and Republican Tom Foley remain the front runners in volatile, tightening primary races for governor, according to a Quinnipiac University poll released today.

Lamont’s 9-percentage point lead over Dan Malloy in the Democratic race has been nearly halved in three weeks to 5 points, while Tom Foley’s 35-point cushion over Michael Fedele in the GOP contest has shrunk to 15 points.

The poll of likely voters in next Tuesday’s primaries found Malloy and Fedele making inroads since the previous poll on July 15, before advertising turned sharply negative in both races.

Foley now leads Fedele, 41 percent to 26 percent, with Oz Griebel at 13 percent, but 63 percent of GOP voters say they could change their minds. Three weeks ago, it was Foley with 48 percent to 13 percent for Fedele and 7 percent for Griebel.

“Foley’s negatives have risen, probably due in part to Fedele’s TV ads,” said Schwartz, the poll’s director. “There is still a lot of voter uncertainty in this race, but with less than a week to go, there isn’t much time left for Fedele.”

Lamont leads Malloy, 45 percent to 40 percent, with 14 undecided and many voters saying they could yet change their minds. On July 15, Lamont led, 46 percent to 37 percent, with 16 percent undecided.

“Lamont still has the edge, but with 14 percent of voters undecided and 43 percent who still could change their mind, it is close enough that Malloy could pull it off,” Schwartz said.

In general-election matchups, Lamont and Malloy have double-digit leads over the Republicans. Foley comes the closest, trailing Lamont by 13 percentage points and Malloy by 15 points.

The two races have their parallels: The front runners are Greenwich businessman, Lamont and Foley, who are largely self-funding their campaigns, promising to bring a fresh eye to a state with a stagnant economy and a projected deficit next year of $3.4 billion.

Malloy and Fedele are Stamford residents and experienced elected officials, casting themselves as ready to the do the job. Malloy was mayor of Stamford for 14 years; Fedele is the lieutenant governor and a former legislator. Each have received $2.5 million in public financing and closed on their opponents after airing their race’s first negative ads.

“I’m afraid that negative campaigning works,” Lamont said Wednesday night, anticipating today’s poll. His own negative ads began shortly before Quinnipiac started polling on July 28 and continued with a mailer Wednesday that questioned Malloy’s ethics.

Foley’s negatives — those with an unfavorable view of him — rose from 9 percent to 24 percent since July 15. Fedele’s jumped from 5 percent to 17 percent. In the Democratic race, the candidate’s favorables did not erode as dramatically, with Malloy’s negatives rising from 8 percent to 12 percent and Lamont’s from 12 to 18 percent.

By 46 percent to 29 percent, Democrats say Lamont has the best chance of winning in Novemember. Republicans favor Foley as the strongest general-election candidate, 51 percent to 23 percent.

Democratic voters are more committed than Republicans to sticking with their nominee. If Malloy wins, only 6 percent of Democrats say they cannot support him; if Lamont, only 7 percent. The loss of base support is greater for the Republicans: Foley, 12 percent; Fedele, 9 percent; and Griebel, 11 percent.

In a statement issued today, the Malloy campaign claimed the momentum.

“This race is tightening because as people really begin making up their minds, they’re moving to Dan,” said Dan Kelly, his campaign manager. “They know he turned around a city, and they think he can turn around a state. They know Dan Malloy has the right kind of experience to be governor. They’re moving away from Ned because they don’t want a CEO to run this state like a business, and they want this to be an election, not an auction.”

Lamont’s campaign responded by saying Democrats see him as their best chance to win the governor’s office for the first time since 1986, despite the race’s negative turn.

“Despite a two-week barrage of Dan Malloy’s false, negative ads and his repetition of four-year-old lies about Ned and his company, Connecticut voters still know that Ned Lamont has the best experience to create jobs and help their families,” said Justine Sessions, Lamont’s communication director.

Griebel, the president of a regional business group, the MetroHartford Alliance, is the only candidate who has not had the funds to advertise on television. He also is the only candidate whose negatives have not gone up.

In a Republican debate on Wednesday, Griebel complained that Foley and Fedele were so focused on scoring against each other that they ignored the substance of the questions.

“It’s like two children in a sand box throwing mud at each other,” he said. “Someone has to be the adult in the room.”

The new poll is based on several telephone surveys, beginning July 28.

From July 28 to August 2, Quinnipiac surveyed 1,299 Connecticut registered voters with a margin of error of plus or minus 2.7 percentage points.  From July 29 to August 2, Quinnipiac conducted separate surveys of 1,003 likely Republican primary voters and 979 likely Democratic primary voters with a margin of error of plus or minus 3.1 percentage points. These likely voters were selected from lists of people who have voted in past elections.