diff --git a/mysql-test/suite/binlog/r/fdle_overflow.result b/mysql-test/suite/binlog/r/fdle_overflow.result
index cb2e2f293ccb0..3fde805de82c2 100644
--- a/mysql-test/suite/binlog/r/fdle_overflow.result
+++ b/mysql-test/suite/binlog/r/fdle_overflow.result
@@ -1,11 +1,10 @@
 SET @saved_dbug= @@GLOBAL.debug_dbug;
-SET @@GLOBAL.debug_dbug= '+d,truncate_fde_at_post_header_len';
+SET @@GLOBAL.debug_dbug=
+'+d,truncate_fde_post_header_len,truncate_fde_used_checksum_alg';
 FLUSH BINARY LOGS;
-SHOW BINLOG EVENTS IN 'master-bin.000002';
 ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error
 SET @@GLOBAL.debug_dbug= '+d,truncate_fde_common_header_len';
 FLUSH BINARY LOGS;
-SHOW BINLOG EVENTS IN 'master-bin.000003';
 ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error
 SET @@GLOBAL.debug_dbug= @saved_dbug;
 RESET MASTER;
diff --git a/mysql-test/suite/binlog/t/fdle_overflow.test b/mysql-test/suite/binlog/t/fdle_overflow.test
index b4a997abe1a88..1163e745ed040 100644
--- a/mysql-test/suite/binlog/t/fdle_overflow.test
+++ b/mysql-test/suite/binlog/t/fdle_overflow.test
@@ -11,12 +11,15 @@ SET @saved_dbug= @@GLOBAL.debug_dbug;
 
 # MDEV-40366: `used_checksum_alg`
 
-SET @@GLOBAL.debug_dbug= '+d,truncate_fde_at_post_header_len';
+SET @@GLOBAL.debug_dbug=
+  '+d,truncate_fde_post_header_len,truncate_fde_used_checksum_alg';
 FLUSH BINARY LOGS;
 
 --let $binlog_file= query_get_value(SHOW BINLOG STATUS, File, 1)
+--disable_query_log
 --error ER_ERROR_WHEN_EXECUTING_COMMAND
 --eval SHOW BINLOG EVENTS IN '$binlog_file'
+--enable_query_log
 
 
 # MDEV-40365: `common_header_len` & `post_header_len`
@@ -25,8 +28,10 @@ SET @@GLOBAL.debug_dbug= '+d,truncate_fde_common_header_len';
 FLUSH BINARY LOGS;
 
 --let $binlog_file= query_get_value(SHOW BINLOG STATUS, File, 1)
+--disable_query_log
 --error ER_ERROR_WHEN_EXECUTING_COMMAND
 --eval SHOW BINLOG EVENTS IN '$binlog_file'
+--enable_query_log
 
 # Clean-up
 SET @@GLOBAL.debug_dbug= @saved_dbug;
diff --git a/mysql-test/suite/rpl/r/rpl_rotate_ev_overflow.result b/mysql-test/suite/rpl/r/rpl_rotate_ev_overflow.result
new file mode 100644
index 0000000000000..7c21805495019
--- /dev/null
+++ b/mysql-test/suite/rpl/r/rpl_rotate_ev_overflow.result
@@ -0,0 +1,19 @@
+SET @saved_dbug= @@GLOBAL.debug_dbug;
+SET @@GLOBAL.debug_dbug= '+d,truncate_fde_post_header_len';
+include/master-slave.inc
+[connection master]
+FLUSH BINARY LOGS;
+CALL mtr.add_suppression('Found invalid event in binary log');
+ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error
+connection slave;
+START SLAVE IO_THREAD;
+CALL mtr.add_suppression('Slave I/O: Relay log write failure');
+include/wait_for_slave_io_error.inc [errno=1595]
+connection master;
+SET @@GLOBAL.debug_dbug= @saved_dbug;
+RESET MASTER;
+connection slave;
+CHANGE MASTER TO master_use_gtid=SLAVE_POS;
+SET @@GLOBAL.gtid_slave_pos='';
+include/start_slave.inc
+include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_rotate_ev_overflow.test b/mysql-test/suite/rpl/t/rpl_rotate_ev_overflow.test
new file mode 100644
index 0000000000000..579d7b4c420ab
--- /dev/null
+++ b/mysql-test/suite/rpl/t/rpl_rotate_ev_overflow.test
@@ -0,0 +1,51 @@
+# MDEV-40647 OOB read in IO Thread if the FDEv does not support Rotate Events
+
+--source include/have_debug.inc
+--source include/have_binlog_format_mixed.inc # should be format-agnostic
+
+SET @saved_dbug= @@GLOBAL.debug_dbug;
+SET @@GLOBAL.debug_dbug= '+d,truncate_fde_post_header_len';
+--let $rpl_skip_start_slave= 1
+# This setup will also RESET MASTER ...
+--source include/master-slave.inc
+# ... which means the binlog file is consistent.
+--let $binlog_file= master-bin.000001
+
+# Use a specific binlog position to avoid the
+# test failing early from other metadata events
+--let $binlog_start= query_get_value(SHOW BINLOG STATUS, Position, 1)
+# Generate the Rotate Event
+FLUSH BINARY LOGS;
+
+
+# Control: SHOW BINLOG EVENTS fails as expected.
+CALL mtr.add_suppression('Found invalid event in binary log');
+--disable_query_log
+  --error ER_ERROR_WHEN_EXECUTING_COMMAND
+  --eval SHOW BINLOG EVENTS IN '$binlog_file' FROM $binlog_start
+--enable_query_log
+
+--connection slave
+--disable_query_log
+  eval CHANGE MASTER TO master_use_gtid=NO,
+    master_log_file='$binlog_file', master_log_pos=$binlog_start;
+--enable_query_log
+START SLAVE IO_THREAD;
+CALL mtr.add_suppression('Slave I/O: Relay log write failure');
+# ER_SLAVE_RELAY_LOG_WRITE_FAILURE
+--let $slave_io_errno= 1595
+# Experiment: The IO thread should fail.
+--source include/wait_for_slave_io_error.inc
+
+# Clean-up
+--connection master
+SET @@GLOBAL.debug_dbug= @saved_dbug;
+RESET MASTER;
+
+--connection slave
+CHANGE MASTER TO master_use_gtid=SLAVE_POS; # restore the default
+--disable_warnings
+  SET @@GLOBAL.gtid_slave_pos=''; # for good measure
+--enable_warnings
+--source include/start_slave.inc
+--source include/rpl_end.inc
diff --git a/sql/log_event_server.cc b/sql/log_event_server.cc
index ec36fc5692682..b005d34e2866c 100644
--- a/sql/log_event_server.cc
+++ b/sql/log_event_server.cc
@@ -2376,8 +2376,9 @@ bool Format_description_log_event::write()
   const size_t buff_size= DBUG_EVALUATE_IF("truncate_fde_common_header_len",
     ST_COMMON_HEADER_LEN_OFFSET, sizeof(buff));
   size_t rec_size= buff_size +
-    DBUG_EVALUATE_IF("truncate_fde_at_post_header_len", 0,
-      BINLOG_CHECKSUM_ALG_DESC_LEN + number_of_event_types);
+    DBUG_EVALUATE_IF("truncate_fde_post_header_len", 0, number_of_event_types) +
+    DBUG_EVALUATE_IF("truncate_fde_used_checksum_alg", 0,
+      BINLOG_CHECKSUM_ALG_DESC_LEN);
   int2store(buff + ST_BINLOG_VER_OFFSET,binlog_version);
   memcpy((char*) buff + ST_SERVER_VER_OFFSET,server_version,ST_SERVER_VER_LEN);
   if (!dont_set_created)
@@ -2416,11 +2417,12 @@ bool Format_description_log_event::write()
     checksum_alg= BINLOG_CHECKSUM_ALG_CRC32;  // Forcing (V) room to fill anyway
   }
   ret= write_header(rec_size) ||
-    write_data(buff, buff_size) ||
-    DBUG_EVALUATE_IF("truncate_fde_at_post_header_len", false,
-       write_data(post_header_len, number_of_event_types) ||
-       write_data(&checksum_byte, sizeof(checksum_byte)) ||
-       write_footer());
+       write_data(buff, buff_size) ||
+        DBUG_EVALUATE_IF("truncate_fde_post_header_len", false,
+          write_data(post_header_len, number_of_event_types)) ||
+        DBUG_EVALUATE_IF("truncate_fde_used_checksum_alg", false,
+          write_data(&checksum_byte, sizeof(checksum_byte))) ||
+       write_footer();
   if (no_checksum)
     checksum_alg= BINLOG_CHECKSUM_ALG_OFF;
   return ret;
diff --git a/sql/slave.cc b/sql/slave.cc
index bbffb3db216e1..5618616b9872f 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -6610,6 +6610,17 @@ static int queue_event(Master_info* mi, const uchar *buf, ulong event_len)
     goto err;
   case ROTATE_EVENT:
   {
+    /*
+      It's normally done in Log_event::read_log_event(),
+      but we bypass it here because it's expensive and costs dynamic memory.
+    */
+    if (unlikely(ROTATE_EVENT >
+      mi->rli.relay_log.description_event_for_queue->number_of_event_types))
+    {
+      // The current FDE does not support `ROTATE_EVENT`.
+      error= ER_SLAVE_RELAY_LOG_WRITE_FAILURE;
+      goto err;
+    }
     Rotate_log_event rev(buf, checksum_alg != BINLOG_CHECKSUM_ALG_OFF ?
                          event_len - BINLOG_CHECKSUM_LEN : event_len,
                          mi->rli.relay_log.description_event_for_queue);