title: Guest accounts invited and added to channels by Welcomebot plugin
description: Mattermost WelcomeBot plugin fails to to validate the membership status when inviting or adding users to channels allowing guest accounts to be added or invited to channels by default.
problem types: CWE-863 Incorrect Authorization
affected:
{
defaultStatus: affected
product: Mattermost Plugins
vendor: Mattermost
versions:
lessThanOrEqual: 7.8.5, status: affected, version: 0, versionType: semver
lessThanOrEqual: 7.10.2, status: affected, version: 0, versionType: semver
status: unaffected, version: 7.8.6
status: unaffected, version: 7.10.3
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 3.5
baseSeverity: LOW
confidentialityImpact: LOW
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: REQUIRED
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
version: 3.1
]
format: CVSS
scenarios: GENERAL
solutions: Update Mattermost to versions 7.8.6, 7.10.3 or higher. Alternatively, update the WelcomeBot plugin to version 1.3.0 or higher.