diff --git a/client/mysql.cc b/client/mysql.cc
index 510420fdf3d..2ea464c2bdf 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -808,7 +808,7 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
     break;
 #endif
   case OPT_CHARSETS_DIR:
-    strmov(mysql_charsets_dir, argument);
+    strmake(mysql_charsets_dir, argument, sizeof(mysql_charsets_dir) - 1);
     charsets_dir = mysql_charsets_dir;
     break;
   case  OPT_DEFAULT_CHARSET:
@@ -861,7 +861,7 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
       if (argument && strlen(argument))
       {
 	default_pager_set= 1;
-	strmov(pager, argument);
+	strmake(pager, argument, sizeof(pager) - 1);
 	strmov(default_pager, pager);
       }
       else if (default_pager_set)
diff --git a/mysql-test/r/mysql.result b/mysql-test/r/mysql.result
index e83bbe97eaa..74b5c42e59b 100644
--- a/mysql-test/r/mysql.result
+++ b/mysql-test/r/mysql.result
@@ -174,4 +174,8 @@ ERROR 2005 (HY000) at line 1: Unknown MySQL server host 'cyrils_superlonghostnam
 1
 ERROR at line 1: DELIMITER cannot contain a backslash character
 ERROR at line 1: DELIMITER cannot contain a backslash character
+1
+1
+1
+1
 End of 5.0 tests
diff --git a/mysql-test/t/mysql.test b/mysql-test/t/mysql.test
index 1af7c6381fe..09e90e2ee2a 100644
--- a/mysql-test/t/mysql.test
+++ b/mysql-test/t/mysql.test
@@ -264,4 +264,10 @@ EOF
 --exec $MYSQL --version 2>&1 > /dev/null
 --enable_quary_log
 
+#
+# bug #26851: Mysql Client --pager Buffer Overflow
+#
+--exec $MYSQL --pager="540bytelengthstringxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" -e "select 1" 2>&1
+--exec $MYSQL --character-sets-dir="540bytelengthstringxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" -e "select 1" 2>&1
+
 --echo End of 5.0 tests
diff --git a/mysys/charset.c b/mysys/charset.c
index 9fb02f1a39f..cce97677b14 100644
--- a/mysys/charset.c
+++ b/mysys/charset.c
@@ -388,7 +388,7 @@ my_bool STDCALL init_available_charsets(myf myflags)
 static my_bool init_available_charsets(myf myflags)
 #endif
 {
-  char fname[FN_REFLEN];
+  char fname[FN_REFLEN + sizeof(MY_CHARSET_INDEX)];
   my_bool error=FALSE;
   /*
     We have to use charset_initialized to not lock on THR_LOCK_charset
@@ -519,7 +519,7 @@ CHARSET_INFO *get_charset(uint cs_number, myf flags)
 
   if (!cs && (flags & MY_WME))
   {
-    char index_file[FN_REFLEN], cs_string[23];
+    char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)], cs_string[23];
     strmov(get_charsets_dir(index_file),MY_CHARSET_INDEX);
     cs_string[0]='#';
     int10_to_str(cs_number, cs_string+1, 10);
@@ -539,7 +539,7 @@ CHARSET_INFO *get_charset_by_name(const char *cs_name, myf flags)
 
   if (!cs && (flags & MY_WME))
   {
-    char index_file[FN_REFLEN];
+    char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)];
     strmov(get_charsets_dir(index_file),MY_CHARSET_INDEX);
     my_error(EE_UNKNOWN_COLLATION, MYF(ME_BELL), cs_name, index_file);
   }
@@ -564,7 +564,7 @@ CHARSET_INFO *get_charset_by_csname(const char *cs_name,
 
   if (!cs && (flags & MY_WME))
   {
-    char index_file[FN_REFLEN];
+    char index_file[FN_REFLEN + sizeof(MY_CHARSET_INDEX)];
     strmov(get_charsets_dir(index_file),MY_CHARSET_INDEX);
     my_error(EE_UNKNOWN_CHARSET, MYF(ME_BELL), cs_name, index_file);
   }