diff --git a/internal/web/service/inbound.go b/internal/web/service/inbound.go
index 2b97d951a..ff5edbb3e 100644
--- a/internal/web/service/inbound.go
+++ b/internal/web/service/inbound.go
@@ -1410,6 +1410,18 @@ func (s *InboundService) UpdateInbound(inbound *model.Inbound) (*model.Inbound,
 	s.normalizeMtprotoSecret(inbound)
 	inbound.SubSortIndex = normalizeSubSortIndex(inbound.SubSortIndex)
 
+	clients, err := s.GetClients(inbound)
+	if err != nil {
+		return inbound, false, err
+	}
+	if inbound.Protocol == model.Hysteria {
+		for _, client := range clients {
+			if client.Auth == "" {
+				return inbound, false, common.NewError("empty client ID")
+			}
+		}
+	}
+
 	oldInbound, err := s.GetInbound(inbound.Id)
 	if err != nil {
 		return inbound, false, err
diff --git a/internal/web/service/inbound_hysteria_auth_test.go b/internal/web/service/inbound_hysteria_auth_test.go
new file mode 100644
index 000000000..9000876e3
--- /dev/null
+++ b/internal/web/service/inbound_hysteria_auth_test.go
@@ -0,0 +1,106 @@
+package service
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/mhsanaei/3x-ui/v3/internal/database"
+	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
+)
+
+func TestUpdateInbound_RejectsHysteriaClientWithoutAuth(t *testing.T) {
+	setupConflictDB(t)
+	seedInboundConflict(t, "in-45001-tcp", "0.0.0.0", 45001, model.VLESS,
+		`{"network":"tcp"}`, `{"clients":[]}`)
+
+	var existing model.Inbound
+	if err := database.GetDB().Where("tag = ?", "in-45001-tcp").First(&existing).Error; err != nil {
+		t.Fatalf("read seeded row: %v", err)
+	}
+
+	update := existing
+	update.Protocol = model.Hysteria
+	update.Settings = `{"clients":[{"email":"hysteria@x","enable":true,"password":"not-hysteria-auth"}]}`
+
+	svc := &InboundService{}
+	if _, _, err := svc.UpdateInbound(&update); err == nil || !strings.Contains(err.Error(), "empty client ID") {
+		t.Fatalf("UpdateInbound error = %v, want empty client ID", err)
+	}
+
+	var reloaded model.Inbound
+	if err := database.GetDB().First(&reloaded, existing.Id).Error; err != nil {
+		t.Fatalf("reload: %v", err)
+	}
+	if reloaded.Protocol != existing.Protocol {
+		t.Fatalf("persisted protocol = %q, want unchanged %q", reloaded.Protocol, existing.Protocol)
+	}
+	if reloaded.Settings != existing.Settings {
+		t.Fatalf("rejected settings were persisted\ngot:  %s\nwant: %s", reloaded.Settings, existing.Settings)
+	}
+}
+
+func TestUpdateInbound_PreservesHysteriaClientAuth(t *testing.T) {
+	setupConflictDB(t)
+	seedInboundConflict(t, "in-45002-udp", "0.0.0.0", 45002, model.Hysteria,
+		`{"network":"hysteria"}`, `{"clients":[]}`)
+
+	var existing model.Inbound
+	if err := database.GetDB().Where("tag = ?", "in-45002-udp").First(&existing).Error; err != nil {
+		t.Fatalf("read seeded row: %v", err)
+	}
+
+	const wantAuth = "hysteria-auth"
+	const password = "not-hysteria-auth"
+	update := existing
+	update.Settings = `{"clients":[{"email":"hysteria@x","enable":true,"password":"` + password + `","auth":"` + wantAuth + `"}]}`
+
+	svc := &InboundService{}
+	if _, _, err := svc.UpdateInbound(&update); err != nil {
+		t.Fatalf("UpdateInbound: %v", err)
+	}
+
+	var reloaded model.Inbound
+	if err := database.GetDB().First(&reloaded, existing.Id).Error; err != nil {
+		t.Fatalf("reload: %v", err)
+	}
+	clients, err := ParseInboundSettingsClients(reloaded.Settings)
+	if err != nil {
+		t.Fatalf("parse persisted clients: %v", err)
+	}
+	if len(clients) != 1 {
+		t.Fatalf("persisted clients = %d, want 1", len(clients))
+	}
+	if clients[0].Auth != wantAuth {
+		t.Fatalf("persisted auth = %q, want %q", clients[0].Auth, wantAuth)
+	}
+	if clients[0].Password != password {
+		t.Fatalf("persisted password = %q, want %q", clients[0].Password, password)
+	}
+}
+
+func TestUpdateInbound_AllowsHysteriaWithoutClients(t *testing.T) {
+	setupConflictDB(t)
+	seedInboundConflict(t, "in-45003-udp", "0.0.0.0", 45003, model.Hysteria,
+		`{"network":"hysteria"}`, `{"clients":[]}`)
+
+	var existing model.Inbound
+	if err := database.GetDB().Where("tag = ?", "in-45003-udp").First(&existing).Error; err != nil {
+		t.Fatalf("read seeded row: %v", err)
+	}
+
+	update := existing
+	update.Remark = "updated without clients"
+
+	svc := &InboundService{}
+	if _, _, err := svc.UpdateInbound(&update); err != nil {
+		t.Fatalf("UpdateInbound: %v", err)
+	}
+
+	var reloaded model.Inbound
+	if err := database.GetDB().First(&reloaded, existing.Id).Error; err != nil {
+		t.Fatalf("reload: %v", err)
+	}
+	if reloaded.Remark != update.Remark {
+		t.Fatalf("persisted remark = %q, want %q", reloaded.Remark, update.Remark)
+	}
+}