Index: Doc/library/os.rst
===================================================================
--- Doc/library/os.rst	(revision 77505)
+++ Doc/library/os.rst	(working copy)
@@ -414,7 +414,13 @@
       provided with Windows.  Newer versions of Python do not use the broken
       implementation from the Windows libraries.
 
+   .. versionchanged:: 2.7
+      Earlier versions would run the *command* string directly with
+      ``cmd.exe /c`` on Windows. Internally, the *command* string is now
+      surrounded with quotes, to support cases where the command itself
+      contains quotes.
 
+
 .. function:: tmpfile()
 
    Return a new file object opened in update mode (``w+b``).  The file has no
Index: Modules/posixmodule.c
===================================================================
--- Modules/posixmodule.c	(revision 77505)
+++ Modules/posixmodule.c	(working copy)
@@ -4984,10 +4984,10 @@
 		if (GetVersion() < 0x80000000 &&
 		    _stricmp(comshell, "command.com") != 0) {
 			/* NT/2000 and not using command.com. */
-			x = i + strlen(s3) + strlen(cmdstring) + 1;
+			x = i + strlen(s3) + strlen(cmdstring) + 3;
 			s2 = (char *)alloca(x);
 			ZeroMemory(s2, x);
-			PyOS_snprintf(s2, x, "%s%s%s", s1, s3, cmdstring);
+			PyOS_snprintf(s2, x, "%s%s\"%s\"", s1, s3, cmdstring);
 		}
 		else {
 			/*