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.
{
"cpes": [
"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*"
],
"severity": "High"
}