diff --git a/contrib/postgres_fdw/deparse.c b/contrib/postgres_fdw/deparse.c
index a3639e9604..ad37a74221 100644
--- a/contrib/postgres_fdw/deparse.c
+++ b/contrib/postgres_fdw/deparse.c
@@ -390,6 +390,22 @@ foreign_expr_walker(Node *node,
 			{
 				Param	   *p = (Param *) node;
 
+				/*
+				 * If it's a MULTIEXPR Param, punt.  We can't tell from here
+				 * whether the referenced sublink/subplan contains any remote
+				 * Vars; if it does, handling that is too complicated to
+				 * consider supporting at present.  Fortunately, MULTIEXPR
+				 * Params are not reduced to plain PARAM_EXEC until the end of
+				 * planning, so we can easily detect this case.  (Normal
+				 * PARAM_EXEC Params are safe to ship because their values
+				 * come from somewhere else in the plan tree; but a MULTIEXPR
+				 * references a sub-select elsewhere in the same targetlist,
+				 * so we'd be on the hook to evaluate it somehow if we wanted
+				 * to handle such cases as direct foreign updates.)
+				 */
+				if (p->paramkind == PARAM_MULTIEXPR)
+					return false;
+
 				/*
 				 * Collation rule is same as for Consts and non-foreign Vars.
 				 */
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 84fd3ad2e0..ebe7bfde23 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -5449,6 +5449,37 @@ DELETE FROM ft2
 (10 rows)
 
 DELETE FROM ft2 WHERE ft2.c1 > 1200;
+-- Test UPDATE with a MULTIEXPR sub-select
+-- (maybe someday this'll be remotely executable, but not today)
+EXPLAIN (verbose, costs off)
+UPDATE ft2 AS target SET (c2, c7) = (
+    SELECT c2 * 10, c7
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+                                                                    QUERY PLAN                                                                     
+---------------------------------------------------------------------------------------------------------------------------------------------------
+ Update on public.ft2 target
+   Remote SQL: UPDATE "S 1"."T 1" SET c2 = $2, c7 = $3 WHERE ctid = $1
+   ->  Foreign Scan on public.ft2 target
+         Output: target.c1, $1, NULL::integer, target.c3, target.c4, target.c5, target.c6, $2, target.c8, (SubPlan 1 (returns $1,$2)), target.ctid
+         Remote SQL: SELECT "C 1", c3, c4, c5, c6, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" > 1100)) FOR UPDATE
+         SubPlan 1 (returns $1,$2)
+           ->  Foreign Scan on public.ft2 src
+                 Output: (src.c2 * 10), src.c7
+                 Remote SQL: SELECT c2, c7 FROM "S 1"."T 1" WHERE (($1::integer = "C 1"))
+(9 rows)
+
+UPDATE ft2 AS target SET (c2, c7) = (
+    SELECT c2 * 10, c7
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+UPDATE ft2 AS target SET (c2) = (
+    SELECT c2 / 10
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
 -- Test UPDATE/DELETE with WHERE or JOIN/ON conditions containing
 -- user-defined operators/functions
 ALTER SERVER loopback OPTIONS (DROP extensions);
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index acd7275c72..83971665e3 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1191,6 +1191,26 @@ DELETE FROM ft2
   RETURNING 100;
 DELETE FROM ft2 WHERE ft2.c1 > 1200;
 
+-- Test UPDATE with a MULTIEXPR sub-select
+-- (maybe someday this'll be remotely executable, but not today)
+EXPLAIN (verbose, costs off)
+UPDATE ft2 AS target SET (c2, c7) = (
+    SELECT c2 * 10, c7
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+UPDATE ft2 AS target SET (c2, c7) = (
+    SELECT c2 * 10, c7
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+
+UPDATE ft2 AS target SET (c2) = (
+    SELECT c2 / 10
+        FROM ft2 AS src
+        WHERE target.c1 = src.c1
+) WHERE c1 > 1100;
+
 -- Test UPDATE/DELETE with WHERE or JOIN/ON conditions containing
 -- user-defined operators/functions
 ALTER SERVER loopback OPTIONS (DROP extensions);