The 171.9-km mountain stage from Sisteron to Nice was decided by a late attack from the FDJ United-Suez rider, who caught her rivals by surprise and held on to claim victory in a tightly contested finish.
The stage win earned Vollering her fifth stint in the yellow jersey at the race and made her the fifth different rider to lead the 2026 edition of the Tour de France Femmes.
Italy's Elisa Longo Borghini of UAE Team ADQ was second on the stage, while Poland's former race leader Kasia Niewiadoma-Phinney of Canyon/SRAM crossed the line third, surrendering the overall lead to Vollering before Sunday's concluding stage.