Heat oil in a large pot over medium heat. Add onion, carrots and celery. Cook, stirring, until the vegetables begin to soften, 6 to 8 minutes. Add bell pepper, garlic, Italian seasoning, pepper and salt and cook, stirring, for 2 minutes.

Add broth, cabbage and tomato; increase the heat to medium-high and bring to a boil. Reduce heat to maintain a simmer, partially cover and cook until all the vegetables are tender, 15 to 20 minutes more. Remove from heat and stir in vinegar.