diff --git a/unittest/libmariadb/ps_bugs.c b/unittest/libmariadb/ps_bugs.c
index 6311179c..b5173a76 100644
--- a/unittest/libmariadb/ps_bugs.c
+++ b/unittest/libmariadb/ps_bugs.c
@@ -3251,7 +3251,7 @@ static int test_mem_overun(MYSQL *mysql)
   strcpy(buffer, "create table t_mem_overun(");
   for (i= 0; i < 1000; i++)
   {
-    sprintf(field, "c%d int, ", i);
+    snprintf(field, sizeof(field), "c%d int, ", i);
     strcat(buffer, field);
   }
   length= (int)strlen(buffer);