CVE-2026-6347 HIGH

CVE-2026-6347: Mattermost Calls plugin exposes TURN server credentials in plaintext in support packets

Vendor Mattermost
Product Mattermost
Weakness CWE-200 · Info exposure
Published May 18, 2026
Last update May 18, 2026
View on NVD All CVEs

CVSS base score

7.6/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:L

What the vulnerability does

01Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to sanitize sensitive configuration fields in the Mattermost Calls plugin which allows an attacker with access to a support packet to obtain TURN server credentials via the plaintext values present in the exported plugin configuration.. Mattermost Advisory ID: MMSA-2026-00605

Key dates

02Disclosure timeline

May 18, 2026 CVE published
May 18, 2026 Record updated