CVE-2026-6342 Details
Description
Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID: MMSA-2026-00601
A vulnerability exists in Mattermost Plugins in versions through 11.5, 11.1.5, 10.13.11, and 11.3.4.0, where the plugins fail to properly validate namespaces. This flaw enables plugin users to subscribe to groups that are not whitelisted by creating groups with prefixes that match those of whitelisted groups.
Users can upgrade to Mattermost Plugins version 11.7 or later 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 May 18, 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 | >= 10.13.0, <= 10.13.11 >= 11.1.0, <= 11.1.5 >= 11.3.0, <= 11.3.4 |
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 |
| May 29, 2026 | Initial Analysis | [email protected] |
| May 18, 2026 | New CVE Received | [email protected] |