diff --git a/mysql-test/main/servers.result b/mysql-test/main/servers.result
index a02c3d6ac74..1460eefaa30 100644
--- a/mysql-test/main/servers.result
+++ b/mysql-test/main/servers.result
@@ -37,11 +37,14 @@ alter server s1 options(host 'server.example.org');
 rename table mysql.servers to mysql.servers_save;
 create table mysql.servers (x int);
 alter server s1 options(host 'server.example.org');
-ERROR HY000: The foreign server name you are trying to reference does not exist. Data source error:  s1
+ERROR HY000: Cannot load from mysql.servers. The table is probably corrupted
+drop server s1;
+ERROR HY000: Cannot load from mysql.servers. The table is probably corrupted
 create server s2 foreign data wrapper foo options(user 'a');
-ERROR HY000: Can't read record in system table
+ERROR HY000: Cannot load from mysql.servers. The table is probably corrupted
 drop table mysql.servers;
 rename table mysql.servers_save to mysql.servers;
+flush privileges;
 drop server s1;
 #
 # MDEV-35641 foreign server "disappears" after ALTERing the servers system table to use innodb and FLUSH PRIVILEGES
@@ -50,3 +53,54 @@ CREATE SERVER s1 FOREIGN DATA WRAPPER mysql OPTIONS (HOST '127.0.0.1');
 ALTER TABLE mysql.servers ENGINE=innodb;
 FLUSH PRIVILEGES;
 drop server s1;
+#
+# MDEV-35622 SEGV, ASAN use-after-poison when reading system table with less than expected number of columns
+# MDEV-37777 upgrade from MySQL 5.7 regression, mysql.servers invalid structure
+#
+# no crash:
+rename table mysql.servers to mysql.servers_save;
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers drop column owner;
+insert into mysql.servers values(0,0,0,0,0,0,0,0);
+flush privileges;
+ERROR HY000: Cannot load from mysql.servers. The table is probably corrupted
+drop table mysql.servers;
+# w/o PK
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers drop primary key;
+insert into mysql.servers values(0,0,0,0,0,0,0,0,0);
+flush privileges;
+ERROR HY000: Cannot load from mysql.servers. The table is probably corrupted
+drop table mysql.servers;
+# upgrade is ok
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers add column Options text;
+create server s1 foreign data wrapper mysql options (host '127.0.0.1');
+flush privileges;
+drop server s1;
+drop table mysql.servers;
+# MySQL 5.7 (MDEV-37777)
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers modify Host char(64) not null, modify Owner char(64) not null;
+create server s1 foreign data wrapper mysql options (host '127.0.0.1');
+flush privileges;
+drop server s1;
+drop table mysql.servers;
+rename table mysql.servers_save to mysql.servers;
+# plugin
+create table mysql.plugin_save like mysql.plugin;
+alter table mysql.plugin drop column dl;
+install soname "ha_example";
+ERROR HY000: Cannot load from mysql.plugin. The table is probably corrupted
+uninstall soname "ha_example";
+ERROR HY000: Cannot load from mysql.plugin. The table is probably corrupted
+drop table mysql.plugin;
+create table mysql.plugin like mysql.plugin_save;
+alter table mysql.plugin drop primary key;
+install soname "ha_example";
+ERROR HY000: Cannot load from mysql.plugin. The table is probably corrupted
+uninstall soname "ha_example";
+ERROR HY000: Cannot load from mysql.plugin. The table is probably corrupted
+drop table mysql.plugin;
+rename table mysql.plugin_save to mysql.plugin;
+# End of 10.11 tests
diff --git a/mysql-test/main/servers.test b/mysql-test/main/servers.test
index f46041bb21c..5ef82173e88 100644
--- a/mysql-test/main/servers.test
+++ b/mysql-test/main/servers.test
@@ -34,12 +34,15 @@ create server s1 foreign data wrapper foo options(user 'a');
 alter server s1 options(host 'server.example.org');
 rename table mysql.servers to mysql.servers_save;
 create table mysql.servers (x int);
---error ER_FOREIGN_SERVER_DOESNT_EXIST
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
 alter server s1 options(host 'server.example.org');
---error ER_CANT_FIND_SYSTEM_REC
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+drop server s1;
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
 create server s2 foreign data wrapper foo options(user 'a');
 drop table mysql.servers;
 rename table mysql.servers_save to mysql.servers;
+flush privileges;
 drop server s1;
 
 --echo #
@@ -50,3 +53,61 @@ CREATE SERVER s1 FOREIGN DATA WRAPPER mysql OPTIONS (HOST '127.0.0.1');
 ALTER TABLE mysql.servers ENGINE=innodb;
 FLUSH PRIVILEGES;
 drop server s1;
+
+--echo #
+--echo # MDEV-35622 SEGV, ASAN use-after-poison when reading system table with less than expected number of columns
+--echo # MDEV-37777 upgrade from MySQL 5.7 regression, mysql.servers invalid structure
+--echo #
+
+--echo # no crash:
+rename table mysql.servers to mysql.servers_save;
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers drop column owner;
+insert into mysql.servers values(0,0,0,0,0,0,0,0);
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+flush privileges;
+drop table mysql.servers;
+
+--echo # w/o PK
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers drop primary key;
+insert into mysql.servers values(0,0,0,0,0,0,0,0,0);
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+flush privileges;
+drop table mysql.servers;
+
+--echo # upgrade is ok
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers add column Options text;
+create server s1 foreign data wrapper mysql options (host '127.0.0.1');
+flush privileges;
+drop server s1;
+drop table mysql.servers;
+
+--echo # MySQL 5.7 (MDEV-37777)
+create table mysql.servers like mysql.servers_save;
+alter table mysql.servers modify Host char(64) not null, modify Owner char(64) not null;
+create server s1 foreign data wrapper mysql options (host '127.0.0.1');
+flush privileges;
+drop server s1;
+drop table mysql.servers;
+rename table mysql.servers_save to mysql.servers;
+
+--echo # plugin
+create table mysql.plugin_save like mysql.plugin;
+alter table mysql.plugin drop column dl;
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+install soname "ha_example";
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+uninstall soname "ha_example";
+drop table mysql.plugin;
+create table mysql.plugin like mysql.plugin_save;
+alter table mysql.plugin drop primary key;
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+install soname "ha_example";
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+uninstall soname "ha_example";
+drop table mysql.plugin;
+rename table mysql.plugin_save to mysql.plugin;
+
+--echo # End of 10.11 tests
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 007af961396..a66e1ec83c1 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -6129,11 +6129,12 @@ mysql_execute_command(THD *thd, bool is_called_from_prepared_stmt)
 
     if ((err_code= drop_server(thd, &lex->server_options)))
     {
-      if (! lex->if_exists() && err_code == ER_FOREIGN_SERVER_DOESNT_EXIST)
+      if (! lex->if_exists() || err_code != ER_FOREIGN_SERVER_DOESNT_EXIST)
       {
         DBUG_PRINT("info", ("problem dropping server %s",
                             lex->server_options.server_name.str));
-        my_error(err_code, MYF(0), lex->server_options.server_name.str);
+        if (!thd->is_error())
+          my_error(err_code, MYF(0), lex->server_options.server_name.str);
       }
       else
       {
diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index 35319c4c2eb..1239d165fc7 100644
--- a/sql/sql_plugin.cc
+++ b/sql/sql_plugin.cc
@@ -1875,6 +1875,19 @@ static bool register_builtin(struct st_maria_plugin *plugin,
 }
 
 
+static bool plugin_table_is_valid(TABLE *table)
+{
+  if (table->s->fields < PLUGIN_FIELDS_COUNT ||
+      table->s->primary_key == MAX_KEY)
+  {
+    my_error(ER_CANNOT_LOAD_FROM_TABLE_V2, MYF(0),
+             table->s->db.str, table->s->table_name.str);
+    return false;
+  }
+  return true;
+}
+
+
 /*
   called only by plugin_init()
 */
@@ -1917,6 +1930,9 @@ static void plugin_load(MEM_ROOT *tmp_root)
     goto end;
   }
 
+  if (!plugin_table_is_valid(table))
+    goto end2;
+
   if (init_read_record(&read_record_info, new_thd, table, NULL, NULL, 1, 0,
                        FALSE))
   {
@@ -1978,6 +1994,7 @@ static void plugin_load(MEM_ROOT *tmp_root)
     sql_print_error(ER_THD(new_thd, ER_GET_ERRNO), my_errno,
                            table->file->table_type());
   end_read_record(&read_record_info);
+end2:
   table->mark_table_for_reopen();
   close_mysql_tables(new_thd);
 end:
@@ -2280,8 +2297,8 @@ bool mysql_install_plugin(THD *thd, const LEX_CSTRING *name,
   WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL);
 
   /* need to open before acquiring LOCK_plugin or it will deadlock */
-  if (! (table = open_ltable(thd, &tables, TL_WRITE,
-                             MYSQL_LOCK_IGNORE_TIMEOUT)))
+  table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);
+  if (!table || !plugin_table_is_valid(table))
     DBUG_RETURN(TRUE);
 
   if (my_load_defaults(MYSQL_CONFIG_NAME, load_default_groups, &argc, &argv, NULL))
@@ -2438,19 +2455,10 @@ bool mysql_uninstall_plugin(THD *thd, const LEX_CSTRING *name,
   WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL);
 
   /* need to open before acquiring LOCK_plugin or it will deadlock */
-  if (! (table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT)))
+  table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);
+  if (!table || !plugin_table_is_valid(table))
     DBUG_RETURN(TRUE);
 
-  if (!table->key_info)
-  {
-    my_printf_error(ER_UNKNOWN_ERROR,
-                    "The table %s.%s has no primary key. "
-                    "Please check the table definition and "
-                    "create the primary key accordingly.", MYF(0),
-                    table->s->db.str, table->s->table_name.str);
-    DBUG_RETURN(TRUE);
-  }
-
   /*
     Pre-acquire audit plugins for events that may potentially occur
     during [UN]INSTALL PLUGIN.
diff --git a/sql/sql_servers.cc b/sql/sql_servers.cc
index 3fa319eb571..c6e06ca3d48 100644
--- a/sql/sql_servers.cc
+++ b/sql/sql_servers.cc
@@ -315,6 +315,20 @@ end:
 }
 
 
+static bool servers_table_is_valid(TABLE *table)
+{
+  if (table->s->fields < SERVERS_FIELDS_COUNT ||
+      table->s->primary_key == MAX_KEY)
+  {
+    my_errno= 1;
+    my_error(ER_CANNOT_LOAD_FROM_TABLE_V2, MYF(0),
+             table->s->db.str, table->s->table_name.str);
+    return false;
+  }
+  return true;
+}
+
+
 /*
   Forget current servers cache and read new servers 
   from the conneciton table.
@@ -358,6 +372,9 @@ bool servers_reload(THD *thd)
     goto end;
   }
 
+  if (!servers_table_is_valid(tables.table))
+    goto end;
+
   if ((return_val= servers_load(thd, &tables)))
   {					// Error. Revert to old list
     /* blast, for now, we have no servers, discuss later way to preserve */
@@ -479,8 +496,10 @@ insert_server(THD *thd, FOREIGN_SERVER *server)
   tables.init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_SERVERS_NAME, 0, TL_WRITE);
 
   /* need to open before acquiring THR_LOCK_plugin or it will deadlock */
-  if (! (table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT)))
+  table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);
+  if (!table || !servers_table_is_valid(table))
     goto end;
+
   table->file->row_logging= 0;                  // Don't log to binary log
 
   /* insert the server into the table */
@@ -559,9 +578,6 @@ store_server_fields(TABLE *table, FOREIGN_SERVER *server)
 
   table->use_all_columns();
 
-  if (table->s->fields < SERVERS_FIELDS_COUNT)
-    return ER_CANT_FIND_SYSTEM_REC;
-
   /*
     "server" has already been prepped by prepare_server_struct_for_<>
     so, all we need to do is check if the value is set (> -1 for port)
@@ -711,8 +727,8 @@ static int drop_server_internal(THD *thd, LEX_SERVER_OPTIONS *server_options)
   if (unlikely((error= delete_server_record_in_cache(server_options))))
     goto end;
 
-  if (unlikely(!(table= open_ltable(thd, &tables, TL_WRITE,
-                                    MYSQL_LOCK_IGNORE_TIMEOUT))))
+  table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);
+  if (!table || !servers_table_is_valid(table))
   {
     error= my_errno;
     goto end;
@@ -839,7 +855,8 @@ int update_server(THD *thd, FOREIGN_SERVER *existing, FOREIGN_SERVER *altered)
 
   tables.init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_SERVERS_NAME, 0, TL_WRITE);
 
-  if (!(table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT)))
+  table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);
+  if (!table || !servers_table_is_valid(table))
   {
     error= my_errno;
     goto end;