CVE-2026-6062 Details
Description
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT request to the subscription edit endpoint.. Mattermost Advisory ID: MMSA-2026-00650
A vulnerability exists in Mattermost versions 11.7.x through 11.7.0, 11.6.x through 11.6.2, 11.5.x through 11.5.5, and 10.11.x through 10.11.17. The issue arises because the application fails to properly validate channel ownership of existing subscriptions before allowing edits. This flaw enables an authenticated attacker to hijack subscriptions from channels to which they do not have access by sending a crafted PUT request to the subscription edit endpoint.
Users can upgrade to Mattermost versions 11.8.0, 11.7.3, 11.6.4, or 10.11.20 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 Jun 22, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://mattermost.com/security-updates | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-639 | Authorization Bypass Through User-Controlled Key | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mattermost mattermost server | >= 10.11.0, < 10.11.18 >= 11.5.0, < 11.5.6 >= 11.6.0, < 11.6.3 >= 11.7.0, < 11.7.1 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 23, 2026 | Initial Analysis | [email protected] |
| Jun 22, 2026 | CVE Modified | CISA-ADP |
| Jun 22, 2026 | New CVE Received | [email protected] |