CVE-2026-3433

MEDIUM

Mattermost fails to scope role_updated websocket events to authorized team and channel members

Title source: cna
STIX 2.1

Description

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to restrict role_updated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change notifications for private teams they are not a member of via the websocket connection.. Mattermost Advisory ID: MMSA-2026-00616

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00616
https://mattermost.com/security-updates

Scores

CVSS v3 4.3
EPSS 0.0018
EPSS Percentile 7.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-200
Status published
Products (9)
Mattermost/Mattermost 10.11.0 - 10.11.15
Mattermost/Mattermost 10.11.0 - 10.11.16
Mattermost/Mattermost 10.11.16
Mattermost/Mattermost 10.11.17
Mattermost/Mattermost 11.5.0 - 11.5.4
Mattermost/Mattermost 11.5.5
Mattermost/Mattermost 11.6.0 - 11.6.1
Mattermost/Mattermost 11.6.2
Mattermost/Mattermost 11.7.0
Published Jun 12, 2026
Tracked Since Jun 12, 2026