Index: Lib/test/string_tests.py
===================================================================
--- Lib/test/string_tests.py	(révision 76700)
+++ Lib/test/string_tests.py	(copie de travail)
@@ -5,6 +5,7 @@
 import unittest, string, sys, struct
 from test import test_support
 from UserList import UserList
+from random import randint
 
 class Sequence:
     def __init__(self, seq='wxyz'): self.seq = seq
@@ -185,6 +186,10 @@
         self.checkequal(-1, '', 'find', 'xx', 1, 1)
         self.checkequal(-1, '', 'find', 'xx', sys.maxint, 0)
 
+        # issue 7458
+        start = randint(sys.maxsize + 1, (sys.maxsize + 1) * 2 - 1)
+        self.checkequal(-1, 'ab', 'find', 'xxx', start, 0)
+
         # For a variety of combinations,
         #    verify that str.find() matches __contains__
         #    and that the found substring is really at that location
@@ -230,6 +235,10 @@
         self.checkraises(TypeError, 'hello', 'rfind')
         self.checkraises(TypeError, 'hello', 'rfind', 42)
 
+        # issue 7458
+        start = randint(sys.maxsize + 1, (sys.maxsize + 1) * 2 - 1)
+        self.checkequal(-1, 'ab', 'rfind', 'xxx', start, 0)
+
     def test_index(self):
         self.checkequal(0, 'abcdefghiabc', 'index', '')
         self.checkequal(3, 'abcdefghiabc', 'index', 'def')
Index: Objects/stringlib/find.h
===================================================================
--- Objects/stringlib/find.h	(révision 76700)
+++ Objects/stringlib/find.h	(copie de travail)
@@ -63,6 +63,8 @@
         end += str_len;
     if (end < 0)
         end = 0;
+    if (end < start)
+        return -1;
 
     return stringlib_find(
         str + start, end - start,
@@ -85,6 +87,8 @@
         end += str_len;
     if (end < 0)
         end = 0;
+    if (end < start)
+        return -1;
 
     return stringlib_rfind(str + start, end - start, sub, sub_len, start);
 }