Bring a large pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente. Reserve 1 cup of pasta water, then drain the pasta and set aside.

In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until softened.

Stir in the minced garlic and cook for an additional 1 minute until fragrant.

Add the zucchini, yellow squash, and red bell pepper to the skillet. Cook for 5-7 minutes until the vegetables are tender.

Stir in the cherry tomatoes and dried oregano. Season with salt and pepper. Cook for another 3-4 minutes until the tomatoes are slightly softened.

Add the cooked pasta to the skillet along with the reserved pasta water, fresh basil, Parmesan cheese, and lemon juice. Toss everything together until well combined and heated through.

Adjust seasoning if necessary and serve immediately.