diff --git a/backend/internal/store/store.go b/backend/internal/store/store.go
index 8ebb949..5337502 100644
--- a/backend/internal/store/store.go
+++ b/backend/internal/store/store.go
@@ -1897,6 +1897,15 @@ func (s *Store) EnsureOwner(handle string) (model.Reader, error) {
 			}
 			cur.Handle = handle
 		}
+		// 老库升级路径：站主在评论区的历史身份行 role 可能是 reader
+		// （多用户之前用 admin 会话评论时自动建的）。登录即纠正成 owner，
+		// 否则升级后站主拿到的会话是 reader 角色，用户管理直接 403。
+		if cur.Role != model.RoleOwner {
+			if _, uerr := s.db.Exec(s.db.Q(`UPDATE users SET role = 'owner' WHERE id = ?`), cur.ID); uerr != nil {
+				return model.Reader{}, uerr
+			}
+			cur.Role = model.RoleOwner
+		}
 		return cur, nil
 	}
 	if !errors.Is(err, ErrNotFound) {
@@ -1913,7 +1922,8 @@ func (s *Store) EnsureOwner(handle string) (model.Reader, error) {
 // （老库里站主行只有 provider='admin'，没有 role）。
 func (s *Store) GetOwner() (model.Reader, error) {
 	r, err := scanReader(s.db.QueryRow(s.db.Q(
-		`SELECT ` + userCols + ` FROM users WHERE role = 'owner' OR provider = 'admin' ORDER BY id LIMIT 1`)))
+		`SELECT ` + userCols + ` FROM users WHERE role = 'owner' OR provider = 'admin'
+		ORDER BY CASE WHEN role = 'owner' THEN 0 ELSE 1 END, id LIMIT 1`)))
 	if errors.Is(err, sql.ErrNoRows) {
 		return model.Reader{}, ErrNotFound
 	}
diff --git a/backend/internal/store/store_test.go b/backend/internal/store/store_test.go
index 33c665f..d472fe0 100644
--- a/backend/internal/store/store_test.go
+++ b/backend/internal/store/store_test.go
@@ -490,3 +490,42 @@ func TestProjectCRUD(t *testing.T) {
 		t.Errorf("after delete: got %v, want ErrNotFound", err)
 	}
 }
+
+// 老库升级：多用户之前以 admin 会话评论会留下 provider=admin、role=reader
+// 的历史身份行。升级后 EnsureOwner 必须把它纠正成 owner——否则站主登录
+// 拿到的是 reader 角色，用户管理直接 403（真实事故）。
+func TestEnsureOwnerPromotesLegacyReaderRow(t *testing.T) {
+	d, err := db.Open("sqlite", ":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer d.Close()
+	st, err := New(d)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// 模拟老库：站主发过评论，留下 role=reader 的 admin 身份行
+	if _, err := st.UpsertReader(model.Reader{Provider: "admin", Handle: "admin", Name: "站主"}); err != nil {
+		t.Fatal(err)
+	}
+	legacy, err := st.GetStaffByHandle("admin")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if legacy.Role != model.RoleReader {
+		t.Fatalf("setup: legacy role = %q, want reader", legacy.Role)
+	}
+
+	owner, err := st.EnsureOwner("admin")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if owner.Role != model.RoleOwner {
+		t.Fatalf("after EnsureOwner: role = %q, want owner", owner.Role)
+	}
+	// 行上是真的改了，不是只改返回值
+	again, _ := st.GetStaffByHandle("admin")
+	if again.Role != model.RoleOwner {
+		t.Fatalf("persisted role = %q, want owner", again.Role)
+	}
+}