diff --git a/bundle-uri.c b/bundle-uri.c
index 3b2e347288c3b7..dfb5a193fff521 100644
--- a/bundle-uri.c
+++ b/bundle-uri.c
@@ -15,6 +15,8 @@
 #include "remote.h"
 #include "trace2.h"
 #include "odb.h"
+#include "transport.h"
+#include "url.h"
 
 static struct {
 	enum bundle_list_heuristic heuristic;
@@ -890,11 +892,59 @@ int fetch_bundle_uri(struct repository *r, const char *uri,
 	return result;
 }
 
+/* protocol of 'uri', or "file" if it has none (bare/UNC/relative path) */
+static void bundle_uri_protocol(const char *uri, struct strbuf *out)
+{
+	const char *p = uri;
+
+	while (is_urlschemechar(p == uri, *p))
+		p++;
+	strbuf_reset(out);
+	if (p > uri && starts_with(p, "://"))
+		strbuf_add(out, uri, p - uri);
+	else
+		strbuf_addstr(out, "file");
+}
+
+/* Drop advertised URIs whose protocol is not allowed (see protocol.*.allow). */
+static void sanitize_bundle_list(struct bundle_list *list)
+{
+	struct remote_bundle_info **skipped;
+	size_t nr = 0, i;
+	struct remote_bundle_info *info;
+	struct hashmap_iter iter;
+	struct strbuf proto = STRBUF_INIT;
+
+	ALLOC_ARRAY(skipped, hashmap_get_size(&list->bundles));
+	hashmap_for_each_entry(&list->bundles, &iter, info, ent) {
+		if (!info->uri)
+			continue;
+		bundle_uri_protocol(info->uri, &proto);
+		/* advertised URIs are not user-provided */
+		if (!is_transport_allowed(proto.buf, 0)) {
+			warning(_("skipping bundle URI '%s': protocol '%s' "
+				  "is not allowed"), info->uri, proto.buf);
+			skipped[nr++] = info;
+		}
+	}
+	strbuf_release(&proto);
+
+	for (i = 0; i < nr; i++) {
+		hashmap_remove(&list->bundles, &skipped[i]->ent, NULL);
+		clear_remote_bundle_info(skipped[i], NULL);
+		free(skipped[i]);
+	}
+
+	free(skipped);
+}
+
 int fetch_bundle_list(struct repository *r, struct bundle_list *list)
 {
 	int result;
 	struct bundle_list global_list;
 
+	sanitize_bundle_list(list);
+
 	/*
 	 * If the creationToken heuristic is used, then the URIs
 	 * advertised by 'list' are not nested lists and instead
diff --git a/odb/source-files.c b/odb/source-files.c
index 6d6a3864812534..d103a1cdd6dc57 100644
--- a/odb/source-files.c
+++ b/odb/source-files.c
@@ -164,7 +164,7 @@ static int odb_source_files_freshen_object(struct odb_source *source,
 }
 
 static int odb_source_files_write_object(struct odb_source *source,
-					 const void *buf, unsigned long len,
+					 const void *buf, size_t len,
 					 enum object_type type,
 					 struct object_id *oid,
 					 struct object_id *compat_oid,
diff --git a/odb/source-inmemory.c b/odb/source-inmemory.c
index 1d4bb5be01d15f..4085f6c6f43091 100644
--- a/odb/source-inmemory.c
+++ b/odb/source-inmemory.c
@@ -227,7 +227,7 @@ static int odb_source_inmemory_count_objects(struct odb_source *source,
 }
 
 static int odb_source_inmemory_write_object(struct odb_source *source,
-					    const void *buf, unsigned long len,
+					    const void *buf, size_t len,
 					    enum object_type type,
 					    struct object_id *oid,
 					    struct object_id *compat_oid UNUSED,
diff --git a/odb/source-loose.c b/odb/source-loose.c
index 95978237bc4d2d..9b5d4ddd232da9 100644
--- a/odb/source-loose.c
+++ b/odb/source-loose.c
@@ -595,7 +595,7 @@ static int odb_source_loose_freshen_object(struct odb_source *source,
 }
 
 static int odb_source_loose_write_object(struct odb_source *source,
-					 const void *buf, unsigned long len,
+					 const void *buf, size_t len,
 					 enum object_type type, struct object_id *oid,
 					 struct object_id *compat_oid_in,
 					 enum odb_write_object_flags flags)
diff --git a/odb/source.h b/odb/source.h
index 0476dca970378d..4cd0f571a6b1db 100644
--- a/odb/source.h
+++ b/odb/source.h
@@ -200,7 +200,7 @@ struct odb_source {
 	 * return 0 on success, a negative error code otherwise.
 	 */
 	int (*write_object)(struct odb_source *source,
-			    const void *buf, unsigned long len,
+			    const void *buf, size_t len,
 			    enum object_type type,
 			    struct object_id *oid,
 			    struct object_id *compat_oid,
diff --git a/t/lib-bundle-uri-protocol.sh b/t/lib-bundle-uri-protocol.sh
index de09b6b02e2485..b1bf940cbd8b9b 100644
--- a/t/lib-bundle-uri-protocol.sh
+++ b/t/lib-bundle-uri-protocol.sh
@@ -214,3 +214,59 @@ test_expect_success "test bundle-uri with $BUNDLE_URI_PROTOCOL:// using protocol
 		>actual &&
 	test_cmp_config_output expect actual
 '
+
+# Advertised bundle URIs are subject to protocol.*.allow; "file" (and bare or
+# UNC paths) is denied by default, so such a URI must be skipped, not fetched.
+advertise_uri () {
+	test_config -C "$BUNDLE_URI_PARENT" bundle.version 1 &&
+	test_config -C "$BUNDLE_URI_PARENT" bundle.mode all &&
+	test_config -C "$BUNDLE_URI_PARENT" bundle.payload.uri "$1"
+}
+
+ignores_advertised_uri () {
+	rm -rf victim &&
+	advertise_uri "$1" &&
+	git -c transfer.bundleURI=true -c protocol.version=2 \
+		clone "$BUNDLE_URI_REPO_URI" victim &&
+	git -C victim for-each-ref refs/bundles/ >refs &&
+	test_must_be_empty refs
+}
+
+test_expect_success "create bundle to advertise" '
+	git -C "$BUNDLE_URI_PARENT" bundle create "$PWD/payload.bundle" main
+'
+
+test_expect_success "ignore non-HTTP(S) bundle URI with $BUNDLE_URI_PROTOCOL://" '
+	ignores_advertised_uri "$PWD/payload.bundle" &&
+	ignores_advertised_uri "file://$PWD/payload.bundle"
+'
+
+test_expect_success "protocol.file.allow=always honors file bundle URI with $BUNDLE_URI_PROTOCOL://" '
+	rm -rf victim &&
+	advertise_uri "$PWD/payload.bundle" &&
+	git -c transfer.bundleURI=true -c protocol.version=2 \
+		-c protocol.file.allow=always \
+		clone "$BUNDLE_URI_REPO_URI" victim &&
+	git -C victim rev-parse --verify refs/bundles/heads/main
+'
+
+# same path via a UNC administrative share (cf. t5580-unc-paths.sh)
+if test_have_prereq CYGWIN
+then
+	UNCPATH="$(cygpath -aw .)"
+elif test_have_prereq MINGW
+then
+	UNCPATH="$(pwd)"
+fi
+case "$UNCPATH" in
+[A-Za-z]:*)
+	WITHOUTDRIVE="${UNCPATH#?:}"
+	UNCPATH="//localhost/${UNCPATH%%:*}\$$WITHOUTDRIVE"
+	test -d "$UNCPATH" && test_set_prereq ADMIN_UNC
+	;;
+esac
+
+test_expect_success ADMIN_UNC "ignore UNC bundle URI with $BUNDLE_URI_PROTOCOL://" '
+	ignores_advertised_uri "$UNCPATH/payload.bundle" &&
+	ignores_advertised_uri "file://$UNCPATH/payload.bundle"
+'
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index 841a6671d1a3c1..4bc82dd9682954 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -261,7 +261,7 @@ test_expect_success '--stdin outside of repository (uses default hash)' '
 	test_cmp expect actual
 '
 
-test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \
+test_expect_success EXPENSIVE,SIZE_T_IS_64BIT \
 		'files over 4GB hash literally' '
 	test-tool genzeros $((5*1024*1024*1024)) >big &&
 	test_oid large5GB >expect &&
@@ -269,7 +269,7 @@ test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \
 	test_cmp expect actual
 '
 
-test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \
+test_expect_success EXPENSIVE,SIZE_T_IS_64BIT \
 		'files over 4GB hash correctly via --stdin' '
 	{ test -f big || test-tool genzeros $((5*1024*1024*1024)) >big; } &&
 	test_oid large5GB >expect &&
@@ -277,7 +277,7 @@ test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \
 	test_cmp expect actual
 '
 
-test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \
+test_expect_success EXPENSIVE,SIZE_T_IS_64BIT \
 		'files over 4GB hash correctly' '
 	{ test -f big || test-tool genzeros $((5*1024*1024*1024)) >big; } &&
 	test_oid large5GB >expect &&
@@ -287,7 +287,7 @@ test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \
 
 # This clean filter does nothing, other than excercising the interface.
 # We ensure that cleaning doesn't mangle large files on 64-bit Windows.
-test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \
+test_expect_success EXPENSIVE,SIZE_T_IS_64BIT \
 		'hash filtered files over 4GB correctly' '
 	{ test -f big || test-tool genzeros $((5*1024*1024*1024)) >big; } &&
 	test_oid large5GB >expect &&