Jason Frerich

**Name of the Vulnerable Software and Affected Versions** Mattermost WelcomeBot plugin (affected versions not specified) **Description** The Mattermost WelcomeBot plugin fails to validate the membership status when inviting or adding users to channels, allowing guest accounts to be added or invited to channels by default. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.