CVE-2026-6347

HIGH

Mattermost Calls plugin exposes TURN server credentials in plaintext in support packets

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00605
https://mattermost.com/security-updates

Scores

CVSS v3 7.6
EPSS 0.0005
EPSS Percentile 16.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-200
Status published
Products (8)
Mattermost/Mattermost 10.11.0 - 10.11.13
Mattermost/Mattermost 10.11.14
Mattermost/Mattermost 11.4.0 - 11.4.3
Mattermost/Mattermost 11.4.4
Mattermost/Mattermost 11.5.0 - 11.5.1
Mattermost/Mattermost 11.5.2
Mattermost/Mattermost 11.6.0
mattermost/mattermost_server 10.11.0 - 10.11.14
Published May 18, 2026
Tracked Since May 18, 2026