diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c
index e84ecd1c98..774a70f63d 100644
--- a/contrib/amcheck/verify_heapam.c
+++ b/contrib/amcheck/verify_heapam.c
@@ -30,6 +30,9 @@ PG_FUNCTION_INFO_V1(verify_heapam);
 /* The number of columns in tuples returned by verify_heapam */
 #define HEAPCHECK_RELATION_COLS 4
 
+/* The largest valid toast va_rawsize */
+#define VARLENA_SIZE_LIMIT 0x3FFFFFFF
+
 /*
  * Despite the name, we use this for reporting problems with both XIDs and
  * MXIDs.
@@ -1414,6 +1417,49 @@ check_tuple_attribute(HeapCheckContext *ctx)
 	 */
 	VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
 
+	/* Toasted attributes too large to be untoasted should never be stored */
+	if (toast_pointer.va_rawsize > VARLENA_SIZE_LIMIT)
+		report_corruption(ctx,
+						  psprintf("toast value %u rawsize %u exceeds limit %u",
+								   toast_pointer.va_valueid,
+								   toast_pointer.va_rawsize,
+								   VARLENA_SIZE_LIMIT));
+
+	if (VARATT_IS_COMPRESSED(&toast_pointer))
+	{
+		ToastCompressionId cmid;
+		bool		valid = false;
+
+		/* Compression should never expand the attribute */
+		if (VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer) > toast_pointer.va_rawsize - VARHDRSZ)
+			report_corruption(ctx,
+							  psprintf("toast value %u external size %u exceeds maximum expected for rawsize %u",
+									   toast_pointer.va_valueid,
+									   VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer),
+									   toast_pointer.va_rawsize));
+
+		/* Compressed attributes should have a valid compression method */
+		cmid = TOAST_COMPRESS_METHOD(&toast_pointer);
+		switch (cmid)
+		{
+			/* List of all valid compression method IDs */
+			case TOAST_PGLZ_COMPRESSION_ID:
+			case TOAST_LZ4_COMPRESSION_ID:
+				valid = true;
+				break;
+
+			/* Recognized but invalid compression method ID */
+			case TOAST_INVALID_COMPRESSION_ID:
+				break;
+
+			/* Intentionally no default here */
+		}
+		if (!valid)
+			report_corruption(ctx,
+							  psprintf("toast value %u has invalid compression method id %d",
+									   toast_pointer.va_valueid, cmid));
+	}
+
 	/* The tuple header better claim to contain toasted values */
 	if (!(infomask & HEAP_HASEXTERNAL))
 	{
diff --git a/src/bin/pg_amcheck/t/004_verify_heapam.pl b/src/bin/pg_amcheck/t/004_verify_heapam.pl
index 4ca7ed297c..ae729336d2 100644
--- a/src/bin/pg_amcheck/t/004_verify_heapam.pl
+++ b/src/bin/pg_amcheck/t/004_verify_heapam.pl
@@ -218,7 +218,7 @@ my $rel = $node->safe_psql('postgres',
 my $relpath = "$pgdata/$rel";
 
 # Insert data and freeze public.test
-use constant ROWCOUNT => 16;
+use constant ROWCOUNT => 18;
 $node->safe_psql(
 	'postgres', qq(
 	INSERT INTO public.test (a, b, c)
@@ -297,7 +297,7 @@ close($file)
 $node->start;
 
 # Ok, Xids and page layout look ok.  We can run corruption tests.
-plan tests => 19;
+plan tests => 21;
 
 # Check that pg_amcheck runs against the uncorrupted table without error.
 $node->command_ok(
@@ -504,7 +504,7 @@ for (my $tupidx = 0; $tupidx < ROWCOUNT; $tupidx++)
 		push @expected,
 		  qr/${header}multitransaction ID 4 equals or exceeds next valid multitransaction ID 1/;
 	}
-	elsif ($offnum == 15)    # Last offnum must equal ROWCOUNT
+	elsif ($offnum == 15)
 	{
 		# Set both HEAP_XMAX_COMMITTED and HEAP_XMAX_IS_MULTI
 		$tup->{t_infomask} |= HEAP_XMAX_COMMITTED;
@@ -514,6 +514,24 @@ for (my $tupidx = 0; $tupidx < ROWCOUNT; $tupidx++)
 		push @expected,
 		  qr/${header}multitransaction ID 4000000000 precedes relation minimum multitransaction ID threshold 1/;
 	}
+	elsif ($offnum == 16)
+	{
+		# Set raw size too large
+		$tup->{c_va_rawsize} = 1073741824;
+
+		$header = header(0, $offnum, 2);
+		push @expected,
+		  qr/${header}toast value \d+ rawsize 1073741824 exceeds limit 1073741823/;
+	}
+	elsif ($offnum == 17)    # Last offnum should equal ROWCOUNT-1
+	{
+		# Set raw size too small.
+		$tup->{c_va_rawsize} = 9998;
+
+		$header = header(0, $offnum, 2);
+		push @expected,
+		  qr/${header}toast value \d+ external size 10000 exceeds maximum expected for rawsize 9998/;
+	}
 	write_tuple($file, $offset, $tup);
 }
 close($file)