N.Y. Real Prop. Tax Law § 1137

§ 1137. Statute of limitations. Every deed given pursuant to the\nprovisions of this article shall be presumptive evidence that the\nproceeding and all proceedings therein and all proceedings prior thereto\nfrom and including the assessment of the real property affected and all\nnotices required by law were regular and in accordance with all\nprovisions of law relating thereto. After two years from the date of the\nrecording of such deed, the presumption shall be conclusive. No\nproceeding to set aside such deed may be maintained unless the\nproceeding is commenced and a notice of pendency of the proceeding is\nfiled in the office of the proper county clerk prior to the time that\nthe presumption becomes conclusive.\n