Is enable_auto_accept_shared_attachments enforced for PCI DSS v4.0?

Yes, Ensure transit gateways have auto accept shared attachments feature disabled. If this setting is disabled, then any VPC that attempts to attach to a transit gateway will need to request authorization, and the account that owns the transit gateway will need to accept the authorization.

terraform-aws-modules/transit-gateway/aws for PCI DSS v4.0

Controls

1 control from PCI DSS v4.0 apply to this module.

Control	Clause	Change
EC2 transit gateways should have auto accept shared attachments disabledec2_transit_gateway_auto_cross_account_attachment_disabled 1.2.8	1.2.8