Section 292BA cures defects only in an assessment or assessment...

Section 292BA cures defects only in an assessment or assessment order and does not extend to a TDS-default order under section 201(1)/(1A). Although such an order may be treated as assessment-like in another statutory context, its legislative character as an order cannot be converted into an assessment order for this curative provision. Mandatory Document Identification Number requirements under the CBDT Circular therefore governed validity. Issuance without a DIN was a substantive legal breach rather than a technical defect, rendering the TDS-default order invalid and requiring its quashing along with the appellate order.