CVE-2026-41128
Authorization Bypass in Craft CMS Allows Arbitrary User Group Removal
Publication date: 2026-04-22
Last updated on: 2026-04-22
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| craftcms | craft_cms | From 5.6.0 (inc) to 5.9.14 (inc) |
| craftcms | craft_cms | 5.9.15 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-862 | The product does not perform an authorization check when an actor attempts to access a resource or perform an action. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in Craft CMS versions 5.6.0 through 5.9.14. It allows a user who only has the 'viewUsers' permission to remove any user from all user groups. The issue arises because the endpoint actionSavePermissions() does not properly check authorization when removing users from groups. While adding users to groups requires proper authorization, removing users does not, so submitting an empty 'groups' value effectively removes all group memberships for a user. This flaw was fixed in version 5.9.15.
How can this vulnerability impact me? :
This vulnerability can impact you by allowing users with minimal permissions (only 'viewUsers') to remove other users from all their user groups. This could lead to unauthorized changes in user roles and permissions, potentially disrupting access controls and security policies within the CMS. It may result in users losing access to resources or privileges they should have, or it could be exploited to weaken the system's security posture.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade Craft CMS to version 5.9.15 or later, where the issue has been patched.