This Corrigendum 3 of ITU-T X.509; Information technology – Open Systems Interconnection – The Directory: Public-key and attribute certificate frameworks. (Covering resolution to defect reports 436, 437, 439, 440, 441, 445, 446 and 449) 1) Correction of the defects reported in defect report 436, 437, 439, 440, 441, 445, 446 and 449. 2) Updates to attribute certificate constraints and deletion of extension matching rules.