diff --git a/mysql-test/main/func_json.result b/mysql-test/main/func_json.result
index 15da9211752a3..a5b21ad20294c 100644
--- a/mysql-test/main/func_json.result
+++ b/mysql-test/main/func_json.result
@@ -3022,4 +3022,68 @@ x
 NULL
 SELECT 1 FROM (SELECT JSON_REMOVE(46, DATE(NULL)) AS x EXCEPT SELECT 1) AS d WHERE NOT(NOT(x > 10)) AND (x < 1 OR x > 1);
 1
+#
+# MDEV-40572 SIGSEGV in JSON_OVERLAPS() on a truncated nested JSON object with different character sets/collations
+#
+SET @col=@@collation_connection;
+SET @char=@@character_set_connection;
+SET collation_connection=ucs2_general_ci;
+SELECT JSON_OVERLAPS ('{"B":{}}', '{"B":{') AS exp_ucs2;
+exp_ucs2
+0
+Warnings:
+Warning	4037	Unexpected end of JSON text in argument 2 to function 'json_overlaps'
+SET character_set_connection=utf16;
+SELECT JSON_OVERLAPS ('{"B":{}}', '{"B":{') AS exp_utf16;
+exp_utf16
+0
+Warnings:
+Warning	4037	Unexpected end of JSON text in argument 2 to function 'json_overlaps'
+SET @@collation_connection=@col;
+SET @@character_set_connection=@char;
+#
+# MDEV-40165 JSON_EQUAL/JSON_NORMALIZE/JSON_CONTAINS error handling
+#
+CREATE TABLE t(c1 JSON, c2 JSON);
+INSERT INTO t VALUES ('{"a":1,"b":2}', '{"b":2E0, "a":1E0}'),
+(NULL, '["a", "b"]'),
+('{"r": 1}', NULL),
+('[{"a": 3}, {"d": [1, 2, 3]}]', '[{"d": [1E0, 2E0, 3E0]}, {"a":3E0}]');
+SELECT c1, JSON_EQUALS(c1, '{"r": 1E0}') AS je_c1_const FROM t;
+c1	je_c1_const
+{"a":1,"b":2}	0
+NULL	NULL
+{"r": 1}	1
+[{"a": 3}, {"d": [1, 2, 3]}]	0
+SELECT c1, c2, JSON_EQUALS(c1, c2) AS je_c1_c2 FROM t;
+c1	c2	je_c1_c2
+{"a":1,"b":2}	{"b":2E0, "a":1E0}	1
+NULL	["a", "b"]	NULL
+{"r": 1}	NULL	NULL
+[{"a": 3}, {"d": [1, 2, 3]}]	[{"d": [1E0, 2E0, 3E0]}, {"a":3E0}]	0
+SELECT c1, JSON_CONTAINS(c1, '{"r": 1E0}') AS jc_c1_const FROM t;
+c1	jc_c1_const
+{"a":1,"b":2}	0
+NULL	NULL
+{"r": 1}	1
+[{"a": 3}, {"d": [1, 2, 3]}]	0
+SELECT c1, c2, JSON_CONTAINS(c1, c2) AS jc_c1_c2 FROM t;
+c1	c2	jc_c1_c2
+{"a":1,"b":2}	{"b":2E0, "a":1E0}	1
+NULL	["a", "b"]	NULL
+{"r": 1}	NULL	NULL
+[{"a": 3}, {"d": [1, 2, 3]}]	[{"d": [1E0, 2E0, 3E0]}, {"a":3E0}]	1
+SELECT c1, JSON_OVERLAPS(c1, '{"r": 1E0}') AS jo_c1_const FROM t;
+c1	jo_c1_const
+{"a":1,"b":2}	0
+NULL	NULL
+{"r": 1}	1
+[{"a": 3}, {"d": [1, 2, 3]}]	0
+SELECT c1, c2, JSON_OVERLAPS(c1, c2) AS jo_c1_c2 FROM t;
+c1	c2	jo_c1_c2
+{"a":1,"b":2}	{"b":2E0, "a":1E0}	1
+NULL	["a", "b"]	NULL
+{"r": 1}	NULL	NULL
+[{"a": 3}, {"d": [1, 2, 3]}]	[{"d": [1E0, 2E0, 3E0]}, {"a":3E0}]	1
+DROP TABLE t;
 # End of 10.11 Test
diff --git a/mysql-test/main/func_json.test b/mysql-test/main/func_json.test
index 58b806c78bdbc..6c181ce40f096 100644
--- a/mysql-test/main/func_json.test
+++ b/mysql-test/main/func_json.test
@@ -2150,4 +2150,39 @@ SELECT x FROM (SELECT 1 AS x UNION SELECT 2) AS t WHERE x IN (  SELECT JSON_REPL
 SELECT ( WITH RECURSIVE x ( x ) AS (WITH RECURSIVE x ( x ) AS ( SELECT 1 UNION SELECT x + 1 FROM x ) SELECT json_array_append ( '[[], [], []]' , NOT ( NULL LIKE 'ABC%' ) , 315 ))  SELECT x FROM x WHERE  x > 10 AND  x < 1) AS x;
 SELECT 1 FROM (SELECT JSON_REMOVE(46, DATE(NULL)) AS x EXCEPT SELECT 1) AS d WHERE NOT(NOT(x > 10)) AND (x < 1 OR x > 1);
 
+--echo #
+--echo # MDEV-40572 SIGSEGV in JSON_OVERLAPS() on a truncated nested JSON object with different character sets/collations
+--echo #
+
+SET @col=@@collation_connection;
+SET @char=@@character_set_connection;
+
+SET collation_connection=ucs2_general_ci;
+SELECT JSON_OVERLAPS ('{"B":{}}', '{"B":{') AS exp_ucs2;
+SET character_set_connection=utf16;
+SELECT JSON_OVERLAPS ('{"B":{}}', '{"B":{') AS exp_utf16;
+
+SET @@collation_connection=@col;
+SET @@character_set_connection=@char;
+
+--echo #
+--echo # MDEV-40165 JSON_EQUAL/JSON_NORMALIZE/JSON_CONTAINS error handling
+--echo #
+
+CREATE TABLE t(c1 JSON, c2 JSON);
+INSERT INTO t VALUES ('{"a":1,"b":2}', '{"b":2E0, "a":1E0}'),
+                     (NULL, '["a", "b"]'),
+                     ('{"r": 1}', NULL),
+                     ('[{"a": 3}, {"d": [1, 2, 3]}]', '[{"d": [1E0, 2E0, 3E0]}, {"a":3E0}]');
+
+SELECT c1, JSON_EQUALS(c1, '{"r": 1E0}') AS je_c1_const FROM t;
+SELECT c1, c2, JSON_EQUALS(c1, c2) AS je_c1_c2 FROM t;
+
+SELECT c1, JSON_CONTAINS(c1, '{"r": 1E0}') AS jc_c1_const FROM t;
+SELECT c1, c2, JSON_CONTAINS(c1, c2) AS jc_c1_c2 FROM t;
+
+SELECT c1, JSON_OVERLAPS(c1, '{"r": 1E0}') AS jo_c1_const FROM t;
+SELECT c1, c2, JSON_OVERLAPS(c1, c2) AS jo_c1_c2 FROM t;
+DROP TABLE t;
+
 --echo # End of 10.11 Test
diff --git a/sql/item_jsonfunc.cc b/sql/item_jsonfunc.cc
index 1681b555ca5e3..6acf31a8f6753 100644
--- a/sql/item_jsonfunc.cc
+++ b/sql/item_jsonfunc.cc
@@ -4877,24 +4877,24 @@ int compare_nested_object(json_engine_t *js, json_engine_t *value)
   if (json_normalize_engine(&je, &a_res, a.ptr(), a.length(), value->s.cs))
   {
     value->s.error= je.s.error;
-    value->s.c_str= je.s.c_str;
     goto error;
   }
   if (json_normalize_engine(&je, &b_res, b.ptr(), b.length(), value->s.cs))
   {
     js->s.error= je.s.error;
-    js->s.c_str= je.s.c_str;
     goto error;
   }
 
   result= strcmp(a_res.str, b_res.str) ? 0 : 1;
 
-  error:
+error:
   dynstr_free(&a_res);
   dynstr_free(&b_res);
 
   return MY_TEST(result);
 }
+
+
 int json_find_overlap_with_object(json_engine_t *js, json_engine_t *value,
                                   bool compare_whole)
 {