Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to check the correct permissions which allows authenticated users who only have permission to invite non-guest users to a team to add guest users to that team via the API to add a single user to a team.
CVE ID: CVE-2025-3446
CVSS Base Severity: MEDIUM
CVSS Base Score: 4.3
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Vendor: Mattermost
Product: Mattermost
EPSS Score: 0.02% (probability of being exploited)
EPSS Percentile: 4.91% (scored less or equal to compared to others)
EPSS Date: 2025-06-13 (when was this score calculated)