Medium (4.3) in mattermost mattermost. EPSS 0.2% chance of exploitation in the next 30 days.
Mattermost versions 9.5.x <= 9.5.7, 9.10.x <= 9.10.0 fail to enforce proper access controls which allows any authenticated user, including guests, to mark any channel inside any team as read for any user.
Severity
CVSS 3.1
4.3 medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS
0.2% chance of exploitation in the next 30 days; higher than 15% of CVEs (scores of 2026-10-31)