diff --git a/midx.c b/midx.c
index 76c3f92cc3..05fe99f8ca 100644
--- a/midx.c
+++ b/midx.c
@@ -906,6 +906,48 @@ static int compare_pair_pos_vs_id(const void *_a, const void *_b)
 	return b->pack_int_id - a->pack_int_id;
 }
 
+/*
+ * Return whether the pack index contains an entry with both "oid" and
+ * "offset". A pack index may contain duplicate OIDs, so an arbitrary
+ * OID lookup is not enough to validate a particular offset.
+ *
+ * Do not use offset_to_pack_pos() here: it may consult an optional '.rev'
+ * file, which is verified separately, or build an in-memory reverse index
+ * that remains attached to the pack. Verify the MIDX directly against its
+ * source pack index instead.
+ */
+static int pack_index_has_oid_at_offset(struct packed_git *p,
+					const struct object_id *oid,
+					off_t offset)
+{
+	struct object_id candidate;
+	uint32_t pos, i;
+
+	if (!bsearch_pack(oid, p, &pos))
+		return 0;
+
+	if (nth_packed_object_offset(p, pos) == offset)
+		return 1;
+
+	for (i = pos; i > 0; i--) {
+		if (nth_packed_object_id(&candidate, p, i - 1) ||
+		    !oideq(&candidate, oid))
+			break;
+		if (nth_packed_object_offset(p, i - 1) == offset)
+			return 1;
+	}
+
+	for (i = pos + 1; i < p->num_objects; i++) {
+		if (nth_packed_object_id(&candidate, p, i) ||
+		    !oideq(&candidate, oid))
+			break;
+		if (nth_packed_object_offset(p, i) == offset)
+			return 1;
+	}
+
+	return 0;
+}
+
 /*
  * Limit calls to display_progress() for performance reasons.
  * The interval here was arbitrarily chosen.
@@ -1015,7 +1057,6 @@ int verify_midx_file(struct odb_source_packed *source, unsigned flags)
 	for (i = 0; i < m->num_objects + m->num_objects_in_base; i++) {
 		struct object_id oid;
 		struct pack_entry e;
-		off_t m_offset, p_offset;
 
 		if (i > 0 && pairs[i-1].pack_int_id != pairs[i].pack_int_id &&
 		    nth_midxed_pack(m, pairs[i-1].pack_int_id)) {
@@ -1040,12 +1081,16 @@ int verify_midx_file(struct odb_source_packed *source, unsigned flags)
 			break;
 		}
 
-		m_offset = e.offset;
-		p_offset = find_pack_entry_one(&oid, e.p);
-
-		if (m_offset != p_offset)
-			midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
-				    pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
+		/*
+		 * Check that the exact offset recorded in the MIDX
+		 * belongs to this OID. A pack index may contain
+		 * duplicate OIDs, in which case an arbitrary OID lookup
+		 * can return a different, equally valid copy than the
+		 * one selected by the MIDX writer.
+		 */
+		if (!pack_index_has_oid_at_offset(e.p, &oid, e.offset))
+			midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64),
+				    pairs[i].pos, oid_to_hex(&oid), e.offset);
 
 		midx_display_sparse_progress(progress, i + 1);
 	}
diff --git a/t/helper/test-find-pack.c b/t/helper/test-find-pack.c
index 28d5b1fe09..51093a7030 100644
--- a/t/helper/test-find-pack.c
+++ b/t/helper/test-find-pack.c
@@ -11,12 +11,15 @@
  * Display the path(s), one per line, of the packfile(s) containing
  * the given object.
  *
+ * With '--show-offset', display the offset selected by
+ * find_pack_entry_one() instead of the packfile path.
+ *
  * If '--check-count <n>' is passed, then error out if the number of
  * packfiles containing the object is not <n>.
  */
 
 static const char *const find_pack_usage[] = {
-	"test-tool find-pack [--check-count <n>] <object>",
+	"test-tool find-pack [--check-count <n>] [--show-offset] <object>",
 	NULL
 };
 
@@ -24,11 +27,13 @@ int cmd__find_pack(int argc, const char **argv)
 {
 	struct object_id oid;
 	struct packed_git *p;
-	int count = -1, actual_count = 0;
+	int count = -1, actual_count = 0, show_offset = 0;
 	const char *prefix = setup_git_directory(the_repository);
 
 	struct option options[] = {
 		OPT_INTEGER('c', "check-count", &count, "expected number of packs"),
+		OPT_BOOL(0, "show-offset", &show_offset,
+			 "show matching pack offsets"),
 		OPT_END(),
 	};
 
@@ -40,8 +45,13 @@ int cmd__find_pack(int argc, const char **argv)
 		die("cannot parse %s as an object name", argv[0]);
 
 	repo_for_each_pack(the_repository, p) {
-		if (find_pack_entry_one(&oid, p)) {
-			printf("%s\n", p->pack_name);
+		off_t offset = find_pack_entry_one(&oid, p);
+
+		if (offset) {
+			if (show_offset)
+				printf("%"PRIuMAX"\n", (uintmax_t)offset);
+			else
+				printf("%s\n", p->pack_name);
 			actual_count++;
 		}
 	}
diff --git a/t/t5308-pack-detect-duplicates.sh b/t/t5308-pack-detect-duplicates.sh
index 4ff8f5b449..493ebbc4af 100755
--- a/t/t5308-pack-detect-duplicates.sh
+++ b/t/t5308-pack-detect-duplicates.sh
@@ -77,6 +77,20 @@ test_expect_success 'lookup in duplicated pack' '
 	test_cmp expect actual
 '
 
+test_expect_success 'verify MIDX containing duplicated pack objects' '
+	git multi-pack-index write &&
+	test-tool read-midx --show-objects .git/objects >midx-objects &&
+	midx_offset=$(
+		awk -v oid="$LO_SHA1" "\$1 == oid { print \$2 }" <midx-objects
+	) &&
+	lookup_offset=$(
+		test-tool find-pack --check-count=1 --show-offset "$LO_SHA1"
+	) &&
+	test "$midx_offset" -ne "$lookup_offset" &&
+	git multi-pack-index verify &&
+	git fsck --full
+'
+
 test_expect_success 'duplicate entries remain in pack reverse index' '
 	clear_packs &&
 	{