Input validation

Improper check in CheckboxGroup in com.vaadin:vaadin-checkbox-flow versions 1.2.0 prior to 2.0.0 (Vaadin 12.0.0 prior to 14.0.0), 2.0.0 prior to 3.0.0 (Vaadin 14.0.0 prior to 14.5.0), 3.0.0 through 4.0.1 (Vaadin 15.0.0 through 17.0.11), 14.5.0 through 14.6.7 (Vaadin 14.5.0 through 14.6.7), and 18.0.0 through 20.0.5 (Vaadin 18.0.0 through 20.0.5) allows attackers to modify the value of a disabled Checkbox inside enabled CheckboxGroup component via unspecified vectors.