GHSA-7PFV-HR63-H7CW

Vulnerability from github – Published: 2026-03-09 19:45 – Updated: 2026-03-10 18:39
VLAI?
Summary
Admidio: Event participation IDOR - non-leaders can register other users for events via user_uuid parameter
Details

Vulnerability

In modules/events/events_function.php, the event participation logic allows any user who can participate in an event to register OTHER users by manipulating the user_uuid GET parameter.

Line 47: $getUserUuid = admFuncVariableIsValid($_GET, 'user_uuid', 'uuid', ...) Line 424: if ($event->possibleToParticipate() || $participants->isLeader($gCurrentUserId))

The condition uses || (OR), meaning if possibleToParticipate() returns true (event is open for participation), ANY user - not just leaders - can specify a different user_uuid and register/cancel participation for that user.

The code then operates on $user->getValue('usr_id') (the target user from user_uuid) rather than the current user.

Impact

  • Register unwilling users for events (potential harassment/spam)
  • Cancel other users' event participation
  • Manipulate event participant counts and comments
  • If events have participation limits, fill slots with unwanted registrations

Fix

For non-leader users, force user_uuid to the current user:

if (!$participants->isLeader($gCurrentUserId)) {
    $getUserUuid = $gCurrentUser->getValue('usr_uuid');
}
Severity ?
0.0 (None)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N
5.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "admidio/admidio"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-30927"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-09T19:45:20Z",
    "nvd_published_at": "2026-03-10T17:40:16Z",
    "severity": "MODERATE"
  },
  "details": "## Vulnerability\n\nIn `modules/events/events_function.php`, the event participation logic allows any user who can participate in an event to register OTHER users by manipulating the `user_uuid` GET parameter.\n\nLine 47: `$getUserUuid = admFuncVariableIsValid($_GET, \u0027user_uuid\u0027, \u0027uuid\u0027, ...)`\nLine 424: `if ($event-\u003epossibleToParticipate() || $participants-\u003eisLeader($gCurrentUserId))`\n\nThe condition uses `||` (OR), meaning if `possibleToParticipate()` returns true (event is open for participation), ANY user - not just leaders - can specify a different `user_uuid` and register/cancel participation for that user.\n\nThe code then operates on `$user-\u003egetValue(\u0027usr_id\u0027)` (the target user from user_uuid) rather than the current user.\n\n## Impact\n- Register unwilling users for events (potential harassment/spam)\n- Cancel other users\u0027 event participation\n- Manipulate event participant counts and comments\n- If events have participation limits, fill slots with unwanted registrations\n\n## Fix\nFor non-leader users, force `user_uuid` to the current user:\n```php\nif (!$participants-\u003eisLeader($gCurrentUserId)) {\n    $getUserUuid = $gCurrentUser-\u003egetValue(\u0027usr_uuid\u0027);\n}\n```",
  "id": "GHSA-7pfv-hr63-h7cw",
  "modified": "2026-03-10T18:39:33Z",
  "published": "2026-03-09T19:45:20Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Admidio/admidio/security/advisories/GHSA-7pfv-hr63-h7cw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-30927"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Admidio/admidio/issues/1985"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Admidio/admidio/commit/e47f70cc3cbcdb39635fdbaaef02d19f604b8c3e"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Admidio/admidio"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Admidio: Event participation IDOR - non-leaders can register other users for events via user_uuid parameter"
}


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