Description
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to require re-entry of the stored client secret when validating an outgoing OAuth connection, which allows an authenticated user with permission to manage outgoing OAuth connections to obtain the secret via pointing the token URL at an attacker-controlled endpoint and triggering validation.. Mattermost Advisory ID: MMSA-2026-00761
Published: 2026-10-16
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

References
Link Providers
https://mattermost.com/security-updates cve-icon cve-icon
History

Fri, 16 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 16 Oct 2026 07:15:00 +0000

Type Values Removed Values Added
Description Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to require re-entry of the stored client secret when validating an outgoing OAuth connection, which allows an authenticated user with permission to manage outgoing OAuth connections to obtain the secret via pointing the token URL at an attacker-controlled endpoint and triggering validation.. Mattermost Advisory ID: MMSA-2026-00761
Title Outgoing OAuth connection client secret exposure during connection validation
Weaknesses CWE-201
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-10-16T12:03:18.956Z

Reserved: 2026-08-11T12:04:08.947Z

Link: CVE-2026-19541

cve-icon Vulnrichment

Updated: 2026-10-16T12:03:11.351Z

cve-icon NVD

Status : Received

Published: 2026-10-16T07:17:12.520

Modified: 2026-10-16T13:16:56.750

Link: CVE-2026-19541

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-16T15:30:14Z

Weaknesses
  • CWE-201

    Insertion of Sensitive Information Into Sent Data