description: This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave. A user that is removed from an iMessage group could rejoin the group.
problem types: A user that is removed from an iMessage group could rejoin the group
affected:
{
product: macOS
vendor: Apple
versions:
lessThan: 11.2, status: affected, version: unspecified, versionType: custom
}