diff --git a/src/nvim/bufwrite.c b/src/nvim/bufwrite.c
index cf158bf545..efc30b71a0 100644
--- a/src/nvim/bufwrite.c
+++ b/src/nvim/bufwrite.c
@@ -1669,9 +1669,9 @@ restore_backup:
 #endif
   if (!filtering) {
     add_quoted_fname(IObuff, IOSIZE, buf, fname);
-    // Append the filename to the message ID.
+    // Append the filename (without trailing char) to the message ID.
     char msg_id[IOSIZE + 14] = "nvim.bufwrite ";
-    strncat(msg_id + 14, IObuff, strlen(IObuff) - 1);
+    xstrlcat(msg_id, IObuff, 14 + strlen(IObuff));
     bool insert_space = false;
     if (write_info.bw_conv_error) {
       xstrlcat(IObuff, _(" CONVERSION ERROR"), IOSIZE);
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index 022509b933..3a679e6454 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -132,9 +132,9 @@ void filemess(buf_T *buf, char *name, char *s)
   msg_scrolled_ign = true;
   // may truncate the message to avoid a hit-return prompt
   if (*s == NUL) {
-    // Append the filename to the message ID.
+    // Append the filename (without trailing char) to the message ID.
     char msg_id[IOSIZE + 14] = "nvim.bufwrite ";
-    strncat(msg_id + 14, IObuff, strlen(IObuff) - 1);
+    xstrlcat(msg_id, IObuff, 14 + strlen(IObuff));
     msg_progress(IObuff, msg_id, "running", 0, false, true);
   } else {
     msg_outtrans(msg_may_trunc(false, IObuff), 0, false);