How to get global up vector?

I have a character who needs to jump, but it also can change rotation a bit (lean forward/backwards) which prevents it from jumping properly. Here's my jump code:

 if ((isGrounded)&& (Input.GetButtonDown("Jump"))) {
                 this.rigidbody.isKinematic=false;
                 kinematic=false;
                 isGrounded = false;
                 jumping = 3;
                 this.rigidbody.AddForce(new Vector3 (0,jumpForce,0));
                 
             }