GHSA-45V9-W9FH-33J6 Mattermost fails to properly validate post props

Mattermost versions 10.2.x = 10.2.0, 9.11.x = 9.11.5, 10.0.x = 10.0.3, 10.1.x = 10.1.3 fail to properly validate post props which allows a malicious authenticated user to cause a crash via a malicious post...