N.Y. Estates, Powers & Trusts Law § 11-1.7 – Limitations on powers and immunities of executors and

testamentary trustees

(a) The attempted grant to an executor, testamentary trustee, or inter vivos trustee, or his or her successor, of any of the following enumerated powers or immunities is contrary to public policy:
1. (1) The exoneration of such fiduciary from liability for failure to exercise reasonable care, diligence and prudence.
2. (2) The power to make a binding and conclusive fixation of the value of any asset for purposes of distribution, allocation or otherwise.
(b) The attempted grant in any will or trust of any power or immunity in contravention of the terms of this section shall be void but shall not be deemed to render such will or trust invalid as a whole, and the remaining terms of the instrument shall, so far as possible, remain effective.
(c) Any person interested in an estate or trust may contest the validity of any purported grant of any power or immunity within the purview of this section without diminishing or affecting adversely his or her interest in the estate or trust any provision in any will or trust to the contrary notwithstanding.