Index: include/regex
===================================================================
--- include/regex
+++ include/regex
@@ -4265,6 +4265,9 @@
     if (__first != __last && *__first == '\\')
     {
         _ForwardIterator __t1 = _VSTD::next(__first);
+        if (__t1 == __last)
+            __throw_regex_error<regex_constants::error_escape>();
+
         _ForwardIterator __t2 = __parse_decimal_escape(__t1, __last);
         if (__t2 != __t1)
             __first = __t2;
Index: test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
===================================================================
--- test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
+++ test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
@@ -33,6 +33,7 @@
 {
     assert(error_escape_thrown("[\\a]"));
     assert(error_escape_thrown("\\a"));
+    assert(error_escape_thrown("\\"));
 
     assert(error_escape_thrown("[\\e]"));
     assert(error_escape_thrown("\\e"));