diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 5211c3b3f..8df719aa9 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -201,6 +201,9 @@ const pool<IdString> &RTLIL::builtin_ff_cell_types() {
 
 RTLIL::Const::Const(const std::string &str)
 {
+	if (str.size() * 8 > 0x1000000)
+		throw std::length_error("RTLIL Const width must be less than 2^24");
+
 	flags = RTLIL::CONST_FLAG_STRING;
 	bits.reserve(str.size() * 8);
 	for (int i = str.size()-1; i >= 0; i--) {
@@ -214,6 +217,12 @@ RTLIL::Const::Const(const std::string &str)
 
 RTLIL::Const::Const(int val, int width)
 {
+	if (width < 0)
+		throw std::length_error("RTLIL Const width must not be negative");
+
+	if (width > 0x1000000)
+		throw std::length_error("RTLIL Const width must be less than 2^24");
+
 	flags = RTLIL::CONST_FLAG_NONE;
 	bits.reserve(width);
 	for (int i = 0; i < width; i++) {
@@ -224,6 +233,12 @@ RTLIL::Const::Const(int val, int width)
 
 RTLIL::Const::Const(RTLIL::State bit, int width)
 {
+	if (width < 0)
+		throw std::length_error("RTLIL Const width must not be negative");
+
+	if (width > 0x1000000)
+		throw std::length_error("RTLIL Const width must be less than 2^24");
+
 	flags = RTLIL::CONST_FLAG_NONE;
 	bits.reserve(width);
 	for (int i = 0; i < width; i++)
@@ -232,6 +247,10 @@ RTLIL::Const::Const(RTLIL::State bit, int width)
 
 RTLIL::Const::Const(const std::vector<bool> &bits)
 {
+
+	if (bits.size() > 0x1000000)
+		throw std::length_error("RTLIL Const width must be less than 2^24");
+
 	flags = RTLIL::CONST_FLAG_NONE;
 	this->bits.reserve(bits.size());
 	for (const auto &b : bits)
@@ -296,6 +315,10 @@ std::string RTLIL::Const::as_string() const
 
 RTLIL::Const RTLIL::Const::from_string(const std::string &str)
 {
+
+	if (str.size() > 0x1000000)
+		throw std::length_error("RTLIL width must be less than 2^24");
+
 	Const c;
 	c.bits.reserve(str.size());
 	for (auto it = str.rbegin(); it != str.rend(); it++)