From 3111f3d70ce08764b18f887b1824205b9f133503 Mon Sep 17 00:00:00 2001
From: kolaente <k@knt.li>
Date: Mon, 23 Mar 2026 16:08:59 +0100
Subject: [PATCH] test: add IDOR test for task attachment ReadOne
 (GHSA-jfmm-mjcp-8wq2)

---
 pkg/webtests/task_attachment_idor_test.go | 49 +++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 pkg/webtests/task_attachment_idor_test.go

diff --git a/pkg/webtests/task_attachment_idor_test.go b/pkg/webtests/task_attachment_idor_test.go
new file mode 100644
index 000000000..f8c272e9b
--- /dev/null
+++ b/pkg/webtests/task_attachment_idor_test.go
@@ -0,0 +1,49 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-present Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package webtests
+
+import (
+	"testing"
+
+	"code.vikunja.io/api/pkg/models"
+	"code.vikunja.io/api/pkg/web/handler"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestTaskAttachmentIDOR(t *testing.T) {
+	t.Run("Cannot read attachment from inaccessible task via accessible task ID", func(t *testing.T) {
+		// Attachment 4 belongs to task 34 (owned by user 13, inaccessible to testuser1).
+		// Task 1 is accessible to testuser1.
+		// Requesting GET /tasks/1/attachments/4 should fail because the attachment
+		// does not belong to task 1.
+		testHandler := webHandlerTest{
+			user: &testuser1,
+			strFunc: func() handler.CObject {
+				return &models.TaskAttachment{}
+			},
+			t: t,
+		}
+
+		_, err := testHandler.testReadOneWithUser(nil, map[string]string{
+			"task":       "1", // task accessible to testuser1
+			"attachment": "4", // attachment belonging to task 34, NOT accessible to testuser1
+		})
+		require.Error(t, err)
+		assertHandlerErrorCode(t, err, models.ErrCodeTaskAttachmentDoesNotExist)
+	})
+}