Mayor Pete Buttigieg of South Bend, Indiana, and California Sen. Kamala Harris both achieved 6 percent in the poll, while Minnesota Sen. Amy Klobuchar and former Texas Rep. Beto O’Rourke raked in 3 percent of respondents.

Businessman Andrew Yang garnered 2 percent support, and all other candidates polled at 1 percent or less.

Biden’s standing in Wednesday’s survey marks his most significant edge in CNN’s primary polling since he announced his campaign in late April and dominated the Democratic field with 39 percent support.

His advantage in the latest CNN poll, conducted in the days following the fourth Democratic debate last week, also comes despite a plurality of respondents judging that Warren outperformed Biden during the televised forum.

Among those who watched or paid close attention to news coverage of the Ohio debate, 28 percent said Warren “did the best job,” and only 15 percent said Biden’s showing was superior.

White House allies and Republican lawmakers over the past month have targeted Biden relentlessly with unfounded allegations that he led the Obama administration's efforts to fire a Ukrainian prosecutor in order to protect his son's business interests in the region.

Meanwhile, other recent polls have shown Warren overtaking Biden in the Democratic nominating contest, and candidates such as Buttigieg and Klobuchar have sought to make a more forceful case for themselves to the center-left voters largely backing Biden.

Biden also failed to eclipse a handful of his opponents in fundraising for the third quarter of this year, amassing just $15.2 million in the three months ending in September. Sanders raised $25 million, Warren raised $24.6 million and Buttigieg raised $19.1 million during that same period.

Besides Biden, the poll’s other obvious beneficiaries are Klobuchar and O’Rourke, who have both moved closer to appearing on stage for the fifth party-sanctioned primary debate next month.

To participate, candidates must achieve at least 3 percent support in four polls approved by the Democratic National Committee and pick up contributions from 165,000 donors by Nov. 13.

The survey is Klobuchar’s third qualifying poll and O’Rourke’s second. Eight candidates have already met the threshold for the Atlanta-area debate on Nov. 20.

The CNN poll was conducted Oct. 17-20, surveying a random national sample of 1,003 adults including 424 registered voters who are Democrats or Democratic-leaning independents.

The margins of sampling error are plus or minus 3.7 percentage points for the full sample and 5.8 percentage points for results among potential Democratic voters.