Executive brief
Winter CMS's backend account management feature allows authenticated administrators and staff members to view sensitive profile information of other backend users without proper authorization checks. An attacker with any level of backend access can enumerate all user accounts and retrieve their email addresses, names, roles, and security status. While passwords are masked, the exposed data enables account targeting and privilege mapping for further attacks.
Technical details
The vulnerability is an authorization bypass (CWE-639) in the Backend\Controllers\MyAccount class. The FormController behavior exposes create, update, and preview actions that accept a user-supplied record ID via the URL. The formFindModelObject() method was not scoped to the authenticated user, allowing attackers to query the unscoped Backend\Models\User model. Exploitation requires network access and a valid backend user account (with any privilege level) but involves GET requests with no CSRF token requirement. Backend user IDs are sequential and trivially enumerated. The preview action discloses first name, last name, login, email, and avatar; the update action additionally exposes role, group membership, superuser flag, and throttle state. Write operations were blocked by authorization guards, so the confirmed impact is unauthorized information disclosure. Fixed in v1.2.14 by adding route guards and scoping form queries to the authenticated user.
Affected products
- Winter CMS winter/wn-backend-module 1.2.13
Timeline
- 2026-08-20: disclosed: GHSA-mpmw-f6h6-3g26 published
- 2026-08-20: patched: Fixed in v1.2.14 with commit cdbc8f5a23db27f72ccec658a8e5769e6d9f6dcb