CVE-2026-3115 Details
Description
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594
A vulnerability exists in Mattermost versions 11.2.x through 11.2.2, 10.11.x through 10.11.10, 11.4.x through 11.4.0, and 11.3.x through 11.3.1. These versions fail to properly restrict view permissions when accessing group member IDs, allowing authenticated guest users to enumerate user IDs beyond their permitted visibility range via the group retrieval endpoint.
Users can upgrade to Mattermost versions 11.5.0 or 11.6.0 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Mar 26, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://mattermost.com/security-updates | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mattermost mattermost server | >= 10.11.0, < 10.11.11 >= 11.2.0, < 11.2.3 >= 11.3.0, < 11.3.2 11.4.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Mar 30, 2026 | Initial Analysis | [email protected] |
| Mar 26, 2026 | New CVE Received | [email protected] |