diff --git a/mysql-test/suite/innodb/r/innodb-fk-virtual.result b/mysql-test/suite/innodb/r/innodb-fk-virtual.result
index b39e770c729..2537e7f534e 100644
--- a/mysql-test/suite/innodb/r/innodb-fk-virtual.result
+++ b/mysql-test/suite/innodb/r/innodb-fk-virtual.result
@@ -84,3 +84,53 @@ select * from b;
 cola	v_cola	p_cola	c_cola
 10	2	2	12
 drop table b, a;
+#
+# MDEV-41666 Corruption on statement rollback when
+#    ON UPDATE SET NULL affects the base column
+#
+CREATE TABLE t18 (
+c5 INT NOT NULL,
+PRIMARY KEY (c5)
+) ENGINE=InnoDB;
+CREATE TABLE t21 (
+c1 INT NOT NULL,
+c2 INT DEFAULT NULL,
+c2v INT AS (c2 DIV 1), c1v INT AS (FLOOR(c1)),
+KEY i15 (c2v, c1v),
+CONSTRAINT t21_ibfk_1 FOREIGN KEY (c2) REFERENCES t18 (c5) ON UPDATE SET NULL
+) ENGINE=InnoDB;
+INSERT INTO t18 (c5) VALUES (1), (2);
+INSERT INTO t21 (c1, c2) VALUES (0, 1);
+UPDATE t18 SET c5 = 3;
+ERROR 23000: Duplicate entry '3' for key 'PRIMARY'
+SELECT c5 FROM t18 ORDER BY c5;
+c5
+1
+2
+SELECT c1, c2 FROM t21;
+c1	c2
+0	1
+DROP TABLE t21, t18;
+CREATE TABLE parent (
+id INT PRIMARY KEY
+) ENGINE=InnoDB;
+CREATE TABLE child (
+a INT DEFAULT NULL,
+parent_id INT DEFAULT NULL,
+av INT AS (IFNULL(a, 0)), pv INT AS (IFNULL(parent_id, 0)),
+KEY idx_functional (av, pv),
+CONSTRAINT fk_parent FOREIGN KEY (parent_id) REFERENCES parent (id)
+ON DELETE SET NULL
+) ENGINE=InnoDB;
+INSERT INTO parent VALUES (1);
+INSERT INTO child(a, parent_id) VALUES (NULL, 1);
+START TRANSACTION;
+DELETE FROM parent WHERE id = 1;
+ROLLBACK;
+SELECT id FROM parent;
+id
+1
+SELECT a, parent_id FROM child;
+a	parent_id
+NULL	1
+DROP TABLE child, parent;
diff --git a/mysql-test/suite/innodb/t/innodb-fk-virtual.test b/mysql-test/suite/innodb/t/innodb-fk-virtual.test
index 094fda35abb..8be0ed7f768 100644
--- a/mysql-test/suite/innodb/t/innodb-fk-virtual.test
+++ b/mysql-test/suite/innodb/t/innodb-fk-virtual.test
@@ -59,3 +59,59 @@ delete from a;
 select * from a;
 select * from b;
 drop table b, a;
+
+--echo #
+--echo # MDEV-41666 Corruption on statement rollback when
+--echo #    ON UPDATE SET NULL affects the base column
+--echo #
+CREATE TABLE t18 (
+  c5 INT NOT NULL,
+  PRIMARY KEY (c5)
+) ENGINE=InnoDB;
+
+CREATE TABLE t21 (
+  c1 INT NOT NULL,
+  c2 INT DEFAULT NULL,
+  c2v INT AS (c2 DIV 1), c1v INT AS (FLOOR(c1)),
+  KEY i15 (c2v, c1v),
+  CONSTRAINT t21_ibfk_1 FOREIGN KEY (c2) REFERENCES t18 (c5) ON UPDATE SET NULL
+) ENGINE=InnoDB;
+
+INSERT INTO t18 (c5) VALUES (1), (2);
+INSERT INTO t21 (c1, c2) VALUES (0, 1);
+
+# This first changes 1 to 3 and cascades c2 = 1 to c2 = NULL.
+# Updating the second parent row (2 to 3) then hits the duplicate
+# primary key. The whole statement must roll back, including the
+# functional-index update in t21.
+--error ER_DUP_ENTRY
+UPDATE t18 SET c5 = 3;
+SELECT c5 FROM t18 ORDER BY c5;
+SELECT c1, c2 FROM t21;
+DROP TABLE t21, t18;
+
+# Bug#39872048: DELETE with ON DELETE SET NULL must preserve all functional
+# index key parts when its effects are rolled back.
+CREATE TABLE parent (
+  id INT PRIMARY KEY
+) ENGINE=InnoDB;
+
+CREATE TABLE child (
+  a INT DEFAULT NULL,
+  parent_id INT DEFAULT NULL,
+  av INT AS (IFNULL(a, 0)), pv INT AS (IFNULL(parent_id, 0)),
+  KEY idx_functional (av, pv),
+  CONSTRAINT fk_parent FOREIGN KEY (parent_id) REFERENCES parent (id)
+    ON DELETE SET NULL
+) ENGINE=InnoDB;
+
+INSERT INTO parent VALUES (1);
+INSERT INTO child(a, parent_id) VALUES (NULL, 1);
+
+START TRANSACTION;
+DELETE FROM parent WHERE id = 1;
+ROLLBACK;
+
+SELECT id FROM parent;
+SELECT a, parent_id FROM child;
+DROP TABLE child, parent;
diff --git a/storage/innobase/dict/dict0mem.cc b/storage/innobase/dict/dict0mem.cc
index cf4c1e278db..766f42fefb8 100644
--- a/storage/innobase/dict/dict0mem.cc
+++ b/storage/innobase/dict/dict0mem.cc
@@ -964,11 +964,15 @@ dict_mem_fill_vcol_set_for_base_col(
 					table,
 					v_col->base_col[j]->ind)) == 0) {
 
-				if (*v_cols == NULL) {
-					*v_cols = UT_NEW_NOKEY(dict_vcol_set());
+				/* A change to a base column changes the
+				complete secondary-index record. Include
+				every virtual key part of each affected index,
+				so that a cascaded update has the old values
+				required for undo. */
+				for (const auto& v_idx : v_col->v_indexes) {
+					dict_mem_fill_vcol_has_index(
+						v_idx.index, v_cols);
 				}
-
-				(*v_cols)->insert(v_col);
 			}
 		}
 	}