message: [Script] Check script size first in IsStakeModifierSig
  opcode + len + compact signature --> max = 67 bytes
diff: @@ -271,7 +271,9 @@ bool CScript::StartsWithOpcode(const opcodetype opcode) const
  bool CScript::IsStakeModifierSig() const
  {
  - return StartsWithOpcode(OP_STAKEMODIFIER);
  + // opcode + len + compact signature <= 1 + 1 + 65 bytes
  + return (StartsWithOpcode(OP_STAKEMODIFIER) && this->size() > 2 &&
  + this->size() <= 67 && this->at(1) == (int)this->size() - 2);
  }
  bool CScript::IsZerocoinMint() const
  