diff --git a/ChangeLog b/ChangeLog
index 8496406..fcd9008 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2022-04-13  Bruno Haible  <bruno@clisp.org>
+
+	Fix undefined behaviour.
+	* tests/test-shiftseq.c (main2): Make input array larger.
+
 2022-02-12  Bruno Haible  <bruno@clisp.org>
 
 	Update translations.
diff --git a/tests/test-shiftseq.c b/tests/test-shiftseq.c
index 481fc6a..84eada0 100644
--- a/tests/test-shiftseq.c
+++ b/tests/test-shiftseq.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2008, 2018 Free Software Foundation, Inc.
+/* Copyright (C) 2008, 2018, 2022 Free Software Foundation, Inc.
    This file is part of the GNU LIBICONV Library.
 
    The GNU LIBICONV Library is free software; you can redistribute it
@@ -64,7 +64,7 @@
 
 void main2 (void)
 {
-  static const char input[] = "+2D/YQNhB";
+  static const char input[20] = "+2D/YQNhB";
   iconv_t cd;
   char buf[20];