diff --git a/stl/inc/regex b/stl/inc/regex
index 77efc9d32f..a5af788aed 100644
--- a/stl/inc/regex
+++ b/stl/inc/regex
@@ -1499,7 +1499,7 @@ public:
     void _Add_char(_Elem _Ch);
     void _Add_class();
     void _Add_char_to_class(_Elem _Ch);
-    void _Add_range(_Elem _Ex0, _Elem _Ex1);
+    void _Add_range2(_Elem, _Elem);
     void _Add_named_class(_Regex_traits_base::char_class_type, bool = false);
     void _Add_equiv(_FwdIt, _FwdIt, _Difft);
     void _Add_coll(_FwdIt, _FwdIt, _Difft);
@@ -2882,19 +2882,12 @@ void _Builder<_FwdIt, _Elem, _RxTraits>::_Add_char_to_class(_Elem _Ch) { // add
 }
 
 template <class _FwdIt, class _Elem, class _RxTraits>
-void _Builder<_FwdIt, _Elem, _RxTraits>::_Add_range(_Elem _Arg0, _Elem _Arg1) {
+void _Builder<_FwdIt, _Elem, _RxTraits>::_Add_range2(const _Elem _Arg0, const _Elem _Arg1) {
     // add character range to set
-    unsigned int _Ex0;
-    unsigned int _Ex1;
-    if (_Flags & regex_constants::icase) { // change to lowercase range
-        _Ex0 = static_cast<unsigned int>(_Traits.translate_nocase(_Arg0));
-        _Ex1 = static_cast<unsigned int>(_Traits.translate_nocase(_Arg1));
-    } else {
-        _Ex0 = static_cast<typename _RxTraits::_Uelem>(_Arg0);
-        _Ex1 = static_cast<typename _RxTraits::_Uelem>(_Arg1);
-    }
-
+    unsigned int _Ex0                    = static_cast<typename _RxTraits::_Uelem>(_Arg0);
+    const unsigned int _Ex1              = static_cast<typename _RxTraits::_Uelem>(_Arg1);
     _Node_class<_Elem, _RxTraits>* _Node = static_cast<_Node_class<_Elem, _RxTraits>*>(_Current);
+
     for (; _Ex0 <= _Ex1 && _Ex1 < _Get_bmax(); ++_Ex0) { // set a bit
         if (!_Node->_Small) {
             _Node->_Small = new _Bitmap;
@@ -2913,7 +2906,7 @@ void _Builder<_FwdIt, _Elem, _RxTraits>::_Add_range(_Elem _Arg0, _Elem _Arg1) {
             }
 
             _Node->_Ranges->_Insert(static_cast<_Elem>(_Ex0));
-            _Node->_Ranges->_Insert(static_cast<_Elem>(_Ex1));
+            _Node->_Ranges->_Insert(_Arg1);
         }
     }
 }
@@ -4113,16 +4106,22 @@ void _Parser<_FwdIt, _Elem, _RxTraits>::_ClassRanges() { // check for valid clas
                 _Error(regex_constants::error_range); // set precedes or follows dash
             }
 
-            if (_Flags & regex_constants::collate) { // translate ends of range
-                _Val  = _Traits.translate(static_cast<_Elem>(_Val));
+            _Elem _Chr2 = static_cast<_Elem>(_Val);
+
+            // translate ends of range
+            if (_Flags & regex_constants::icase) {
+                _Chr1 = _Traits.translate_nocase(_Chr1);
+                _Chr2 = _Traits.translate_nocase(_Chr2);
+            } else if (_Flags & regex_constants::collate) {
                 _Chr1 = _Traits.translate(_Chr1);
+                _Chr2 = _Traits.translate(_Chr2);
             }
 
-            if (static_cast<typename _RxTraits::_Uelem>(_Val) < static_cast<typename _RxTraits::_Uelem>(_Chr1)) {
+            if (static_cast<typename _RxTraits::_Uelem>(_Chr2) < static_cast<typename _RxTraits::_Uelem>(_Chr1)) {
                 _Error(regex_constants::error_range);
             }
 
-            _Nfa._Add_range(_Chr1, static_cast<_Elem>(_Val));
+            _Nfa._Add_range2(_Chr1, _Chr2);
         } else if (_Ret == _Prs_chr) {
             _Nfa._Add_char_to_class(static_cast<_Elem>(_Val));
         }
diff --git a/tests/std/tests/Dev10_814245_regex_character_class_crash/test.cpp b/tests/std/tests/Dev10_814245_regex_character_class_crash/test.cpp
index ab6f047f9b..26a8f89605 100644
--- a/tests/std/tests/Dev10_814245_regex_character_class_crash/test.cpp
+++ b/tests/std/tests/Dev10_814245_regex_character_class_crash/test.cpp
@@ -111,12 +111,39 @@ void test_VSO_984741_splitting_a_string_with_a_regex() {
     assert(equal(i, sregex_token_iterator{}, begin(tokens), end(tokens)));
 }
 
+void test_gh_5164_case_insensitive_ranges() {
+    using ch_traits = char_traits<char>;
+    const regex_traits<char> re_traits;
+    for (size_t upper = 0; upper < characterCount; ++upper) {
+        for (size_t lower = 0; lower < characterCount; ++lower) {
+            const string pattern(g_firstCharacters[lower] + "-" + g_secondCharacters[upper]);
+            const char left_bound  = re_traits.translate_nocase(g_inputs[lower][0]);
+            const char right_bound = re_traits.translate_nocase(g_inputs[upper][0]);
+
+            if (ch_traits::lt(right_bound, left_bound)) {
+                g_regexTester.should_throw(pattern, error_range, icase);
+            } else {
+                const regex r(pattern, icase);
+                for (size_t c = 0; c < characterCount; ++c) {
+                    const char input_icase = re_traits.translate_nocase(g_inputs[c][0]);
+                    if (ch_traits::lt(input_icase, left_bound) || ch_traits::lt(right_bound, input_icase)) {
+                        g_regexTester.should_not_match(g_inputs[c], pattern, r);
+                    } else {
+                        g_regexTester.should_match(g_inputs[c], pattern, r);
+                    }
+                }
+            }
+        }
+    }
+}
+
 int main() {
     init_character_strings();
     test_dev10_814245_character_class_should_not_crash();
     test_dev10_723057_normal_to_high_bit_ranges_should_not_throw_error_range();
     test_VSO_153556_singular_classes_can_have_high_bit_set();
     test_VSO_984741_splitting_a_string_with_a_regex();
+    test_gh_5164_case_insensitive_ranges();
 
     return g_regexTester.result();
 }