diff --git a/CMakeLists.txt b/CMakeLists.txt
index 74fdbcbc0c5..617226b5a36 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -194,11 +194,7 @@ ELSE()
 ENDIF()
 
 
-IF("${MYSQL_NO_DASH_VERSION}" VERSION_LESS 11.2)
-  SET(MEMPROTECT_DEFAULT ON)
-ELSE()
-  SET(MEMPROTECT_DEFAULT OFF)
-ENDIF()
+SET(MEMPROTECT_DEFAULT ON)
 
 OPTION(WITH_PROTECT_STATEMENT_MEMROOT "Enable protection of statement's memory root after first SP/PS execution. Turned into account only for debug build"
 ${MEMPROTECT_DEFAULT})
diff --git a/mysql-test/main/ps_mem_leaks.result b/mysql-test/main/ps_mem_leaks.result
index e934c24288c..95a1f317ae0 100644
--- a/mysql-test/main/ps_mem_leaks.result
+++ b/mysql-test/main/ps_mem_leaks.result
@@ -149,6 +149,20 @@ DROP TABLE t1;
 DROP PROCEDURE p1;
 # End of 10.11 tests
 #
+# MDEV-34649: Memory leaks on running DELETE statement in PS mode with positional parameters
+#
+CREATE TABLE t1 (a INT, b VARCHAR(30)) CHARSET=utf8mb4;
+INSERT INTO t1 VALUES (1, 'one'), (0, NULL), (3, 'three'), (4, 'four');
+PREPARE stmt FROM 'DELETE FROM t1 WHERE b=?' ;
+SET @arg00=NULL;
+EXECUTE stmt USING @arg00;
+SET @arg00='one';
+EXECUTE stmt USING @arg00;
+# Clean up
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1;
+# End of 11.1
+#
 # MDEV-34517: Memory leak on re-compilation of a failing statement inside a stored routine
 #
 CREATE TABLE t1 (a INT);
diff --git a/mysql-test/main/ps_mem_leaks.test b/mysql-test/main/ps_mem_leaks.test
index 17baf122d16..951bc7e337a 100644
--- a/mysql-test/main/ps_mem_leaks.test
+++ b/mysql-test/main/ps_mem_leaks.test
@@ -168,6 +168,24 @@ DROP PROCEDURE p1;
 
 --echo # End of 10.11 tests
 
+--echo #
+--echo # MDEV-34649: Memory leaks on running DELETE statement in PS mode with positional parameters
+--echo #
+CREATE TABLE t1 (a INT, b VARCHAR(30)) CHARSET=utf8mb4;
+INSERT INTO t1 VALUES (1, 'one'), (0, NULL), (3, 'three'), (4, 'four');
+PREPARE stmt FROM 'DELETE FROM t1 WHERE b=?' ;
+SET @arg00=NULL;
+EXECUTE stmt USING @arg00;
+SET @arg00='one';
+# Without the patch, attempt to run the same prepared statement the second time
+# would result in memory leaks
+EXECUTE stmt USING @arg00;
+--echo # Clean up
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1;
+
+--echo # End of 11.1
+
 --echo #
 --echo # MDEV-34517: Memory leak on re-compilation of a failing statement inside a stored routine
 --echo #
diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index b7b3b79bbb6..b1fc89b2a28 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -912,6 +912,7 @@ cleanup:
   {
     thd->lex->current_select->save_leaf_tables(thd);
     thd->lex->current_select->leaf_tables_saved= true;
+    thd->lex->current_select->first_cond_optimization= false;
   }
 
   delete deltempfile;