CVE-2026-3115
Authorization Bypass in Mattermost Group Member ID Retrieval
Publication date: 2026-03-26
Last updated on: 2026-03-30
Assigner: Mattermost, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mattermost | mattermost_server | From 10.11.0 (inc) to 10.11.11 (exc) |
| mattermost | mattermost_server | From 11.2.0 (inc) to 11.2.3 (exc) |
| mattermost | mattermost_server | From 11.3.0 (inc) to 11.3.2 (exc) |
| mattermost | mattermost_server | 11.4.0 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-863 | The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability affects certain versions of Mattermost where the system fails to properly enforce view restrictions when retrieving group member IDs. As a result, authenticated guest users can access and enumerate user IDs that are outside their permitted visibility scope by exploiting the group retrieval endpoint.
How can this vulnerability impact me? :
The impact of this vulnerability is that unauthorized users, specifically authenticated guest users, can gain access to user ID information that they should not be able to see. This could lead to privacy concerns and potential information disclosure within the affected Mattermost environment.