diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 73dfe27a6..2e3321a79 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,8 @@
+2010-04-13  John Bowman  <bowman@math.ualberta.ca>
+
+	* cygheap.cc (cwcsdup): Fix allocation size to accommodate sizeof WCHAR.
+	(cwcsdup1): Ditto.
+
 2010-04-12  Corinna Vinschen  <corinna@vinschen.de>
 
 	* include/cygwin/version.h: Bump DLL minor version number to 5.
diff --git a/winsup/cygwin/cygheap.cc b/winsup/cygwin/cygheap.cc
index 7c66d736a..f518aa9e5 100644
--- a/winsup/cygwin/cygheap.cc
+++ b/winsup/cygwin/cygheap.cc
@@ -363,7 +363,7 @@ extern "C" PWCHAR __stdcall
 cwcsdup (const PWCHAR s)
 {
   MALLOC_CHECK;
-  PWCHAR p = (PWCHAR) cmalloc (HEAP_STR, wcslen (s) + 1);
+  PWCHAR p = (PWCHAR) cmalloc (HEAP_STR, (wcslen (s) + 1) * sizeof (WCHAR));
   if (!p)
     return NULL;
   wcpcpy (p, s);
@@ -375,7 +375,7 @@ extern "C" PWCHAR __stdcall
 cwcsdup1 (const PWCHAR s)
 {
   MALLOC_CHECK;
-  PWCHAR p = (PWCHAR) cmalloc (HEAP_1_STR, wcslen (s) + 1);
+  PWCHAR p = (PWCHAR) cmalloc (HEAP_1_STR, (wcslen (s) + 1) * sizeof (WCHAR));
   if (!p)
     return NULL;
   wcpcpy (p, s);