Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to sanitize team email addresses to be visible only to Team Admins, which allows any authenticated user to view team email addresses via the GET /api/v4/channels/{channel_id}/common_teams endpoint
Exploitability
AV:NAC:LPR:LUI:NScope
S:UImpact
C:LI:NA:N4.3/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NInformation Disclosure