diff --git a/library/x509.c b/library/x509.c
index 9c3b0f4..57de545 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -636,18 +636,18 @@
     now->min = st.wMinute;
     now->sec = st.wSecond;
 #else
-    struct tm *lt;
+    struct tm lt;
     time_t tt;
 
     tt = time( NULL );
-    lt = localtime( &tt );
+    localtime_r( &tt, &lt );
 
-    now->year = lt->tm_year + 1900;
-    now->mon = lt->tm_mon + 1;
-    now->day = lt->tm_mday;
-    now->hour = lt->tm_hour;
-    now->min = lt->tm_min;
-    now->sec = lt->tm_sec;
+    now->year = lt.tm_year + 1900;
+    now->mon = lt.tm_mon + 1;
+    now->day = lt.tm_mday;
+    now->hour = lt.tm_hour;
+    now->min = lt.tm_min;
+    now->sec = lt.tm_sec;
 #endif
 }