CVE-2026-3433
Published:June 12, 2026
Updated:June 29, 2026
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
Affected Packages
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.6.0 <v11.6.2Fix Suggestion:
Update to version v11.6.2https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v10.11.0 <v10.11.16Fix Suggestion:
Update to version v10.11.16https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.5.0 <v11.5.5Fix Suggestion:
Update to version v11.5.5github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.6.0 <v11.6.2Fix Suggestion:
Update to version v11.6.2github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.5.0 <v11.5.5Fix Suggestion:
Update to version v11.5.5github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.16Fix Suggestion:
Update to version v10.11.16Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Exposure of Sensitive Information to an Unauthorized Actor
EPSS
Base Score:
0.18