An issue was discovered in Mattermost Server before 5.22.0. The markdown renderer allows attackers to cause a denial of service (client-side), aka MMSA-2020-0017.
An issue was discovered in Mattermost Server before 5.21.0. Socket read operations are not appropriately restricted, which allows attackers to cause a denial of service, aka MMSA-2020-0005.
An issue was discovered in Mattermost Server before 5.20.0. Non-members can receive broadcasted team details via the update_team WebSocket event, aka MMSA-2020-0012.
An issue was discovered in Mattermost Server before 5.19.0. Attackers can discover private channels via the "get channel by name" API, aka MMSA-2020-0004.
An issue was discovered in Mattermost Server before 5.19.0. Attackers can rename a channel and cause a collision with a direct message, aka MMSA-2020-0002.
An issue was discovered in Mattermost Server before 5.18.0, 5.17.2, 5.16.4, 5.15.4, and 5.9.7. CSRF can sometimes occur via a crafted web site for account takeover attacks.
An issue was discovered in Mattermost Server before 5.18.0, 5.17.2, 5.16.4, 5.15.4, and 5.9.7. An attacker can spoof a direct-message channel by changing the type of a channel.