Executive brief
StudioCMS is a website building and content management system. A flaw in the notification preferences API allows any logged-in user to modify notification settings for any other user, including administrators. An attacker could disable admin alerts to hide malicious account creation, modifications, or deletions.
Technical details
The vulnerability is an Insecure Direct Object Reference (IDOR) in the updateUserNotifications endpoint (CWE-639). The endpoint accepts a user ID in the request payload and updates that user's notification preferences, but only checks that the caller is authenticated—it never verifies ownership of the target account. The vulnerable code at packages/studiocms/frontend/pages/studiocms_api/_handlers/dashboard/users.ts:257-311 uses the attacker-controlled ID parameter directly instead of using the logged-in user's ID. Any authenticated visitor (low privilege) can exploit this via a simple POST request to disable notifications for admin accounts, suppressing detection of follow-on attacks. The fix is to add an ownership check unless the caller is an admin.
Affected products
- StudioCMS StudioCMS <=0.4.2
Timeline
- 2026-03-12: disclosed: Advisory published
- 2026-03-12: patched: Fixed in version 0.4.3