diff --git a/as.c b/as.c
index 48327b7..d0e99dd 100644
--- a/as.c
+++ b/as.c
@@ -662,8 +662,8 @@ again:
     }
     swprintf(out_path, out_path_size, L"%ls%ls", out_path, name);
     out_path[out_path_size - 1] = '\0';
-    FILE *f = _wfopen(out_path, L"w");
-    if (f == NULL)
+    FILE *f;
+    if (_wfopen_s(&f, out_path, L"w"))
     {
         MessageBoxW(hWnd, L"Unable to save downloaded profile", _T(PACKAGE_NAME), MB_OK);
         goto done;
diff --git a/config_parser.c b/config_parser.c
index a1bad73..1e70cd9 100644
--- a/config_parser.c
+++ b/config_parser.c
@@ -183,11 +183,7 @@ config_parse(wchar_t *fname)
     FILE *fd = NULL;
     config_entry_t *head, *tail;
 
-    if (fname)
-    {
-        fd = _wfopen(fname, L"r");
-    }
-    if (!fd)
+    if (!fname || _wfopen_s(&fd, fname, L"r"))
     {
         MsgToEventLog(EVENTLOG_ERROR_TYPE, L"Error opening <%ls> in config_parse", fname);
         return NULL;
diff --git a/main.c b/main.c
index a64aab8..f1918fe 100644
--- a/main.c
+++ b/main.c
@@ -202,7 +202,7 @@ _tWinMain(HINSTANCE hThisInstance,
 
 #ifdef DEBUG
     /* Open debug file for output */
-    if (!(o.debug_fp = _wfopen(DEBUG_FILE, L"a+,ccs=UTF-8")))
+    if (_wfopen_s(&o.debug_fp, DEBUG_FILE, L"a+,ccs=UTF-8"))
     {
         /* can't open debug file */
         ShowLocalizedMsg(IDS_ERR_OPEN_DEBUG_FILE, DEBUG_FILE);
diff --git a/misc.c b/misc.c
index 6d811b1..e530a0b 100644
--- a/misc.c
+++ b/misc.c
@@ -937,8 +937,9 @@ ParseManagementAddress(connection_t *c)
             wcsncpy_s(pw_path, MAX_PATH, pw_file, _TRUNCATE);
         }
 
-        FILE *fp = _wfopen(pw_path, L"r");
-        if (!fp || !fgets(c->manage.password, sizeof(c->manage.password), fp))
+        FILE *fp;
+        if (_wfopen_s(&fp, pw_path, L"r")
+            || !fgets(c->manage.password, sizeof(c->manage.password), fp))
         {
             /* This may be normal as not all users may be given access to this secret */
             ret = false;
diff --git a/plap/plap_common.c b/plap/plap_common.c
index 854ef16..5686249 100644
--- a/plap/plap_common.c
+++ b/plap/plap_common.c
@@ -38,7 +38,7 @@ init_debug()
 {
     if (!fp)
     {
-        fp = _wfopen(L"C:\\Windows\\Temp\\openvpn-plap-debug.txt", L"a+,ccs=UTF-8");
+        _wfopen_s(&fp, L"C:\\Windows\\Temp\\openvpn-plap-debug.txt", L"a+,ccs=UTF-8");
     }
     InitializeCriticalSection(&log_write);
 }