diff --git a/examples/rpl-border-router/webserver/httpd-simple.c b/examples/rpl-border-router/webserver/httpd-simple.c
index d8ce76816..7ce984e6a 100644
--- a/examples/rpl-border-router/webserver/httpd-simple.c
+++ b/examples/rpl-border-router/webserver/httpd-simple.c
@@ -128,7 +128,8 @@ PT_THREAD(handle_output(struct httpd_state *s))
   s->script = NULL;
   s->script = httpd_simple_get_script(&s->filename[1]);
   if(s->script == NULL) {
-    strncpy(s->filename, "/notfound.html", sizeof(s->filename));
+    strncpy(s->filename, "/notfound.html", sizeof(s->filename) - 1);
+    s->filename[sizeof(s->filename) - 1] = '\0';
     PT_WAIT_THREAD(&s->outputpt,
                    send_headers(s, http_header_404));
     PT_WAIT_THREAD(&s->outputpt,
@@ -170,7 +171,8 @@ PT_THREAD(handle_input(struct httpd_state *s))
   urlconv_tofilename(s->filename, s->inputbuf, sizeof(s->filename));
 #else /* URLCONV */
   if(s->inputbuf[1] == ISO_space) {
-    strncpy(s->filename, http_index_html, sizeof(s->filename));
+    strncpy(s->filename, http_index_html, sizeof(s->filename) - 1);
+    s->filename[sizeof(s->filename) - 1] = '\0';
   } else {
     s->inputbuf[PSOCK_DATALEN(&s->sin) - 1] = 0;
     strncpy(s->filename, s->inputbuf, sizeof(s->filename));
diff --git a/tools/serial-io/tunslip6.c b/tools/serial-io/tunslip6.c
index aa8b5b9fd..48b0ecd0f 100644
--- a/tools/serial-io/tunslip6.c
+++ b/tools/serial-io/tunslip6.c
@@ -579,8 +579,10 @@ tun_alloc(char *dev, int tap)
    *        IFF_NO_PI - Do not provide packet information
    */
   ifr.ifr_flags = (tap ? IFF_TAP : IFF_TUN) | IFF_NO_PI;
-  if(*dev != 0)
-    strncpy(ifr.ifr_name, dev, IFNAMSIZ);
+  if(*dev != 0) {
+    strncpy(ifr.ifr_name, dev, sizeof(ifr.ifr_name) - 1);
+    ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
+  }
 
   if((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ) {
     close(fd);
@@ -793,9 +795,9 @@ main(int argc, char **argv)
 
     case 's':
       if(strncmp("/dev/", optarg, 5) == 0) {
-	siodev = optarg + 5;
+        siodev = optarg + 5;
       } else {
-	siodev = optarg;
+        siodev = optarg;
       }
       break;
 
@@ -806,10 +808,11 @@ main(int argc, char **argv)
 
     case 't':
       if(strncmp("/dev/", optarg, 5) == 0) {
-	strncpy(tundev, optarg + 5, sizeof(tundev));
+        strncpy(tundev, optarg + 5, sizeof(tundev) - 1);
       } else {
-	strncpy(tundev, optarg, sizeof(tundev));
+        strncpy(tundev, optarg, sizeof(tundev) - 1);
       }
+      tundev[sizeof(tundev) - 1] = '\0';
       break;
 
     case 'a':