4.9

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2026-41657

CVE-2026-41657: Admidio: Cross-Organization Member Data Exposure via Permission Check Mismatch in contacts_data.php

Admidio is an open-source user management solution. Prior to version 5.0.9, the 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. This issue has been patched in version 5.0.9.

(GitHub Advisory)

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CVE-2026-41657

CVE-2026-41657:

4.9

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
admidio/admidio	composer	<= 5.0.8	5.0.9

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability exists due to a permission check mismatch between the frontend UI and the backend data endpoint. The contacts_data.php script, which serves as a backend data provider for the contacts list, performs an inadequate authorization check.

The analysis of the provided information and the commit history of the Admidio/admidio repository confirms this. The commit 7a8536d5cde9c5a3558b8c834d5525f3a5762a19, titled "Members of other organizations could be shown to wrong users #2016", directly addresses the issue.

The patch modifies modules/contacts/contacts_data.php to replace the weak permission check isAdministratorUsers() with the stricter isAdministrator() and an additional check for the contacts_show_all setting. This aligns the backend's authorization logic with the frontend's, preventing unauthorized users from accessing data across different organizations.

The root cause is the incorrect authorization check within the contacts_data.php file. When a request is made with mem_show_filter=3, the script incorrectly grants access to a user who is only a 'user manager' (isAdministratorUsers()) but not a full administrator (isAdministrator()). This allows them to view member data from all organizations, bypassing the intended multi-tenant separation.

Vulnerable functions

contacts_data.php

modules/contacts/contacts_data.php

The file `modules/contacts/contacts_data.php` contains an authorization check that is too permissive. When the `mem_show_filter` parameter is set to 3, the script checks if the current user has 'user administrator' permissions via `$gCurrentUser->isAdministratorUsers()`. This check is weaker than the one in the frontend (`contacts.php`), which correctly verifies full administrator privileges with `$gCurrentUser->isAdministrator()` and an additional setting. This discrepancy allows a user with lower privileges to bypass organization isolation and access data from all organizations by directly calling this endpoint.

Vulnerability Intelligence
Miggo AI

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WAF Protection Rules

WAF Rule

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Reasoning

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