diff --git a/ChangeLog b/ChangeLog
index ac33f5b..85909ca 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,9 @@
    * Fix potential double free if mbedtls_ssl_conf_psk() is called more than
      once and some allocation fails. Cannot be forced remotely. Found by Guido
      Vranken, Intelworks.
+   * Fix potential heap corruption on Windows when
+     mbedtls_x509_crt_parse_path() is passed a path longer than 2GB. Cannot be
+     triggered remotely. Found by Guido Vranken, Interlworks.
    * The X509 max_pathlen constraint was not enforced on intermediate
      certificates. Found by Nicholas Wilson, fix and tests provided by
      Janos Follath. #280 and #319
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 579fbb7..91e4f50 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1099,7 +1099,7 @@
     WCHAR szDir[MAX_PATH];
     char filename[MAX_PATH];
     char *p;
-    int len = (int) strlen( path );
+    size_t len = strlen( path );
 
     WIN32_FIND_DATAW file_data;
     HANDLE hFind;
@@ -1133,7 +1133,7 @@
 
         w_ret = WideCharToMultiByte( CP_ACP, 0, file_data.cFileName,
                                      lstrlenW( file_data.cFileName ),
-                                     p, len - 1,
+                                     p, (int) len - 1,
                                      NULL, NULL );
         if( w_ret == 0 )
             return( MBEDTLS_ERR_X509_FILE_IO_ERROR );