GHSA-g8p8-94f2-28gr Admidio Exposes Cross-Organization Member Data via Permission Check Mismatch in contacts_data.php
SummaryThe `contacts_data.php` endpoint uses a weaker permission check (`isAdministratorUsers()`, requiring only `rol_edit_user=true`) than the frontend UI (`contacts.php`) which correctly requires the stronger `isAdministrator()` (requiring `rol_administrator=true`) and the `contacts_show_all` system setting. A user manager who is not a full administrator can directly request `contacts_data.php?mem_show_filter=3` to retrieve all user records across all organizations in the Admidio instance, bypassing multi-tenant organization isolation.DetailsThe frontend page `contacts.php` and the backend data endpoint `contacts_data.php` have mismatched authorization checks for the "show all organizations" filter (`mem_show_filter=3`).**Frontend guard** at `modules/contacts/contacts.php:80`:This correctly requires both `isAdministrator()` (`rol_administrator=true`) AND the `contacts_show_all` setting.**Backend check** at `modules/contacts/contacts_data.php:235`:This only requires `isAdministratorUsers()` which checks `rol_edit_user=true` — a weaker permission available to non-admin "user manager" roles. The `contacts_show_all` setting is never checked.**The critical difference between the two methods** (from `src/Users/Entity/User.php`):`isAdministrator()` (line 1507): checks the `rol_administrator` flag — full system administrator`isAdministratorUsers()` (line 1625): checks `rol_edit_user` right — user management module access onlyWhen `showAllMembersDatabase=true` reaches `ListConfiguration::getSql()` (at `src/Roles/Entity/ListConfiguration.php:1022-1028`), the generated SQL removes ALL organization filtering:Compare with the default query which includes `cat_org_id = $gCurrentOrgId` to restrict results to the current organization.The cross-org indicator subqueries at line 169 do correctly check `isAdministrator()`, so the `member_other_orga` columns return 0 — but this only affects display indicators, not the actual user data returned.PoC**Prerequisites:** An Admidio instance with at least two organizations sharing the same database. A user account in Organization A assigned to a role with `rol_edit_user=1` but `rol_administrator=0`.**Step 1:** Log in as the user manager account and capture the session cookie.**Step 2:** Request all users across all organizations by directly calling the data endpoint:**Expected behavior:** The request should be rejected or return only current-organization users, since the user is not a full administrator and the frontend never offers filter=3 to non-administrators.**Actual behavior:** The endpoint returns a JSON response containing all users from ALL organizations in the database, including:User UUIDs (`usr_uuid`)Login names (`login_name`)Email addresses (`member_email`)All configured profile fields (names, addresses, phone numbers, etc.)**Step 3:** Verify that users from Organization B (where the attacker has no membership) appear in the results by checking the `member_this_orga` field — it will be `0` for cross-org users.ImpactIn multi-organization Admidio deployments (the primary use case for organization isolation), a user manager in one organization can exfiltrate the complete member directory of all other organizations sharing the same database. Exposed data includes:Full names and all configured profile fieldsEmail addressesLogin names (useful for credential attacks)User UUIDs (useful for targeting other API endpoints)This completely bypasses the multi-tenant organization isolation boundary. The `contacts_show_all` admin setting (intended to control this feature) is also bypassed, meaning even instances where administrators have explicitly disabled cross-org viewing are affected.Recommended FixChange line 235 in `modules/contacts/contacts_data.php` to match the frontend guard at `contacts.php:80`:Additionally, as defense-in-depth, add an early rejection at the top of the file (after line 59) to block the filter value entirely for unauthorized users:
CVSS v3.1 score: 4.9