diff --git a/src/plugins/irc/irc-command.c b/src/plugins/irc/irc-command.c
index 3adfc4654..2395639f0 100644
--- a/src/plugins/irc/irc-command.c
+++ b/src/plugins/irc/irc-command.c
@@ -2475,8 +2475,8 @@ irc_command_kickban (void *data, struct t_gui_buffer *buffer, int argc,
     /* set ban for nick(+host) on channel */
     if (strchr (pos_nick, '@'))
     {
-        length = strlen (pos_nick) + 16;
-        mask = malloc (length + 1);
+        length = strlen (pos_nick) + 16 + 1;
+        mask = malloc (length);
         if (mask)
         {
             pos = strchr (pos_nick, '!');
diff --git a/src/plugins/irc/irc-completion.c b/src/plugins/irc/irc-completion.c
index f37c8f558..f667f1b9a 100644
--- a/src/plugins/irc/irc-completion.c
+++ b/src/plugins/irc/irc-completion.c
@@ -431,8 +431,8 @@ irc_completion_channel_topic_cb (void *data, const char *completion_item,
              * instead of
              *   /topic #test is a test channel
              */
-            length = strlen (ptr_channel->name) + strlen (ptr_channel->topic) + 16;
-            topic = malloc (length + 1);
+            length = strlen (ptr_channel->name) + strlen (ptr_channel->topic) + 16 + 1;
+            topic = malloc (length);
             if (topic)
             {
                 snprintf (topic, length, "%s %s",