diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c
index d099795b..886eb2c3 100644
--- a/src/openvpn/buffer.c
+++ b/src/openvpn/buffer.c
@@ -316,10 +316,10 @@ buf_catrunc(struct buffer *buf, const char *str)
 {
     if (buf_forward_capacity(buf) <= 1)
     {
-        int len = (int) strlen(str) + 1;
+        size_t len = strlen(str);
         if (len < buf_forward_capacity_total(buf))
         {
-            strncpynt((char *)(buf->data + buf->capacity - len), str, len);
+            memcpy(buf->data + buf->capacity - len - 1, str, len + 1);
         }
     }
 }