An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2. An attacker could create fictive system-message posts via webhooks and slash commands, in the v3 or v4 REST API.
Exploitability
AV:NAC:LPR:LUI:NScope
S:UImpact
C:NI:LA:N4.3/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N