diff --git a/mysql-test/suite/parts/inc/part_alter_values.inc b/mysql-test/suite/parts/inc/part_alter_values.inc
index ca18faa5758..d3b63a4610f 100644
--- a/mysql-test/suite/parts/inc/part_alter_values.inc
+++ b/mysql-test/suite/parts/inc/part_alter_values.inc
@@ -78,3 +78,11 @@ if (`SELECT IF('$engine' != 'InnoDB', 1, 0)`)
 
 --remove_files_wildcard $MYSQLTEST_VARDIR/tmp/mdev_27065 *
 --rmdir $MYSQLTEST_VARDIR/tmp/mdev_27065
+
+--echo #
+--echo # MDEV-26127 Assertion `err != DB_DUPLICATE_KEY' failed or InnoDB: Failing assertion: id != 0 on ALTER ... REBUILD PARTITION
+--echo #
+--eval CREATE TABLE t1 (c INT) ENGINE=$engine PARTITION BY KEY(c) PARTITIONS 4;
+LOCK TABLES t1 WRITE, t1 AS a READ;
+ALTER TABLE t1 REBUILD PARTITION p0;
+DROP TABLE t1;
diff --git a/mysql-test/suite/parts/r/partition_alter_innodb.result b/mysql-test/suite/parts/r/partition_alter_innodb.result
index ae3caaa4981..6afa133f989 100644
--- a/mysql-test/suite/parts/r/partition_alter_innodb.result
+++ b/mysql-test/suite/parts/r/partition_alter_innodb.result
@@ -61,3 +61,10 @@ PARTITION p1 VALUES LESS THAN MAXVALUE
 Warnings:
 Warning	1618	<DATA DIRECTORY> table option of old schema is ignored
 DROP TABLE t1;
+#
+# MDEV-26127 Assertion `err != DB_DUPLICATE_KEY' failed or InnoDB: Failing assertion: id != 0 on ALTER ... REBUILD PARTITION
+#
+CREATE TABLE t1 (c INT) ENGINE=InnoDB PARTITION BY KEY(c) PARTITIONS 4;;
+LOCK TABLES t1 WRITE, t1 AS a READ;
+ALTER TABLE t1 REBUILD PARTITION p0;
+DROP TABLE t1;
diff --git a/mysql-test/suite/parts/r/partition_alter_maria.result b/mysql-test/suite/parts/r/partition_alter_maria.result
index 358ffbdfbe7..eca8378430f 100644
--- a/mysql-test/suite/parts/r/partition_alter_maria.result
+++ b/mysql-test/suite/parts/r/partition_alter_maria.result
@@ -95,3 +95,10 @@ PARTITION p1 VALUES LESS THAN MAXVALUE
 Warnings:
 Warning	1618	<INDEX DIRECTORY> table option of old schema is ignored
 DROP TABLE t2;
+#
+# MDEV-26127 Assertion `err != DB_DUPLICATE_KEY' failed or InnoDB: Failing assertion: id != 0 on ALTER ... REBUILD PARTITION
+#
+CREATE TABLE t1 (c INT) ENGINE=Aria PARTITION BY KEY(c) PARTITIONS 4;;
+LOCK TABLES t1 WRITE, t1 AS a READ;
+ALTER TABLE t1 REBUILD PARTITION p0;
+DROP TABLE t1;
diff --git a/mysql-test/suite/parts/r/partition_alter_myisam.result b/mysql-test/suite/parts/r/partition_alter_myisam.result
index 9d76881fdfa..ba1a0fe05c4 100644
--- a/mysql-test/suite/parts/r/partition_alter_myisam.result
+++ b/mysql-test/suite/parts/r/partition_alter_myisam.result
@@ -68,6 +68,13 @@ PARTITION p1 VALUES LESS THAN MAXVALUE
 Warnings:
 Warning	1618	<INDEX DIRECTORY> table option of old schema is ignored
 DROP TABLE t2;
+#
+# MDEV-26127 Assertion `err != DB_DUPLICATE_KEY' failed or InnoDB: Failing assertion: id != 0 on ALTER ... REBUILD PARTITION
+#
+CREATE TABLE t1 (c INT) ENGINE=MyISAM PARTITION BY KEY(c) PARTITIONS 4;;
+LOCK TABLES t1 WRITE, t1 AS a READ;
+ALTER TABLE t1 REBUILD PARTITION p0;
+DROP TABLE t1;
 create table t1 ( c1 int, c2 int, c3 varchar(100)) delay_key_write=1
 partition by key(c1) (
 partition p01 data directory = 'MYSQL_TMP_DIR'
diff --git a/sql/sql_partition.cc b/sql/sql_partition.cc
index 778a3177360..4a0a55f8178 100644
--- a/sql/sql_partition.cc
+++ b/sql/sql_partition.cc
@@ -1,5 +1,5 @@
 /* Copyright (c) 2005, 2017, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2018, MariaDB
+   Copyright (c) 2009, 2022, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -6929,14 +6929,29 @@ static void alter_partition_lock_handling(ALTER_PARTITION_PARAM_TYPE *lpt)
 
 static int alter_close_table(ALTER_PARTITION_PARAM_TYPE *lpt)
 {
+  THD *thd= lpt->thd;
+  TABLE_SHARE *share= lpt->table->s;
   DBUG_ENTER("alter_close_table");
 
-  if (lpt->table->db_stat)
-  {
-    mysql_lock_remove(lpt->thd, lpt->thd->lock, lpt->table);
-    lpt->table->file->ha_close();
-    lpt->table->db_stat= 0;                        // Mark file closed
-  }
+  TABLE *table= thd->open_tables;
+  do {
+    table= find_locked_table(table, share->db.str, share->table_name.str);
+    if (!table)
+    {
+      DBUG_RETURN(0);
+    }
+
+    if (table->db_stat)
+    {
+      mysql_lock_remove(thd, thd->lock, table);
+      if (int error= table->file->ha_close())
+      {
+        DBUG_RETURN(error);
+      }
+      table->db_stat= 0; // Mark file closed
+    }
+  } while ((table= table->next));
+
   DBUG_RETURN(0);
 }