In a medium saucepan, whisk together the vegetable stock and pumpkin puree. Warm the mixture over low heat.
In a large Dutch oven or saucepan, heat the olive oil. Sauté the leeks and shallots over medium-high heat until soft, about 5 minutes. Add the garlic and rosemary and cook one minute more.
Stir in the rice and toast until the edges are opaque and the center pearly white, about 2 minutes. Add the wine and salt to the pan, scraping up any brown bits, and cook until reduced by half.
Add 1 cup of the pumpkin broth to the pan. Bring to a simmer, then turn the heat down to medium low and gently cook until nearly absorbed. Repeat this process, adding stock by ½ cup, until the rice is tender, about 25 minutes. Taste for seasoning. Stir in half the fresh herbs and garnish with the remaining.