An issue was discovered in Mattermost Server before 5.1. An attacker can bypass intended access control (for direct-message channel creation) via the Message slash command.
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
0.6% chance of exploitation in the next 30 days; higher than 49% of CVEs (scores of 2026-10-31)