diff --git a/src/ChangeLog b/src/ChangeLog
index 53344aa7dd9..38779ef8598 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -97,6 +97,8 @@
 	* xfns.c (x_window): Make sprintf buffer a bit bigger
 	to avoid potential buffer overrun.
 
+	* xterm.c (x_io_error_quitter): Don't overrun sprintf buffer.
+
 2011-08-26  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Integer and memory overflow issues (Bug#9196).
diff --git a/src/xterm.c b/src/xterm.c
index c07caec6c78..86393cf411f 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -7900,7 +7900,8 @@ x_io_error_quitter (Display *display)
 {
   char buf[256];
 
-  sprintf (buf, "Connection lost to X server `%s'", DisplayString (display));
+  snprintf (buf, sizeof buf, "Connection lost to X server `%s'",
+	    DisplayString (display));
   x_connection_closed (display, buf);
   return 0;
 }