diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 3cfd1c631..8d89826d7 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-19  Corinna Vinschen  <corinna@vinschen.de>
+
+	* dtable.cc (handle_to_fn): Fix length parameter in call to
+	QueryDosDeviceW (CID 59936).
+
 2014-05-19  Corinna Vinschen  <corinna@vinschen.de>
 
 	* pinfo.cc (pinfo_basic::pinfo_basic): Fix size of progname array in
diff --git a/winsup/cygwin/dtable.cc b/winsup/cygwin/dtable.cc
index 2e9ee5481..0dc548c3d 100644
--- a/winsup/cygwin/dtable.cc
+++ b/winsup/cygwin/dtable.cc
@@ -1,7 +1,7 @@
 /* dtable.cc: file descriptor support.
 
    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
-   2007, 2008, 2009, 2010, 2011, 2012, 2013 Red Hat, Inc.
+   2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -996,7 +996,7 @@ handle_to_fn (HANDLE h, char *posix_fn)
 
       WCHAR fnbuf[64 * 1024];
       if (wcsncasecmp (w32, DEVICE_PREFIX, DEVICE_PREFIX_LEN) != 0
-	  || !QueryDosDeviceW (NULL, fnbuf, sizeof (fnbuf)))
+	  || !QueryDosDeviceW (NULL, fnbuf, sizeof (fnbuf) / sizeof (WCHAR)))
 	{
 	  sys_wcstombs (posix_fn, NT_MAX_PATH, w32, w32len);
 	  return false;