Vikunja is an open-source self-hosted task management platform. Prior to version 2.2.1, `TaskAttachment.ReadOne()` queries attachments by ID only (`WHERE id = ?`), ignoring the task ID from the URL path. The permission check in `CanRead()` validates access to the task specified in the URL, but `ReadOne()` loads a different attachment that may belong to a task in another project. This allows any authenticated user to download or delete any attachment in the system by providing their own accessible task ID with a target attachment ID. Attachment IDs are sequential integers, making enumeration trivial. Version 2.2.1 patches the issue.

Vikunja is an open-source self-hosted task management platform. Starting in version 1.0.0-rc0 and prior to version 2.2.0, unbounded image decoding and resizing during preview generation lets an attacker exhaust CPU and memory with highly compressed but extremely large-dimension images. Version 2.2.0 patches the issue.

Vikunja is an open-source self-hosted task management platform. Starting in version 0.21.0 and prior to version 2.2.0, the Vikunja Desktop Electron wrapper enables `nodeIntegration` in the main BrowserWindow and does not restrict same-window navigations. An attacker who can place a link in user-generated content (task descriptions, comments, project descriptions) can cause the BrowserWindow to navigate to an attacker-controlled origin, where JavaScript executes with full Node.js access, resulting in arbitrary code execution on the victim's machine. Version 2.2.0 patches the issue. ## Root cause Two misconfigurations combine to create this vulnerability: 1. **`nodeIntegration: true`** is set in `BrowserWindow` web preferences (`desktop/main.js:14-16`), giving any page loaded in the renderer full access to Node.js APIs (`require`, `child_process`, `fs`, etc.). 2. **No `will-navigate` or `will-redirect` handler** is registered on the `webContents`. The existing `setWindowOpenHandler` (`desktop/main.js:19-23`) only intercepts `window.open()` calls (new-window requests). It does **not** intercept same-window navigations triggered by: - `<a href="https://...">` links (without `target="_blank"`) - `window.location` assignments - HTTP redirects - `<meta http-equiv="refresh">` tags ## Attack scenario 1. The attacker is a normal user on the same Vikunja instance (e.g., a member of a shared project). 2. The attacker creates or edits a project description or task description containing a standard HTML link, e.g.: `<a href="https://evil.example/exploit">Click here for the updated design spec</a>` 3. The Vikunja frontend renders this link. DOMPurify sanitization correctly allows it -- it is a legitimate anchor tag, not a script injection. Render path example: `frontend/src/views/project/ProjectInfo.vue` uses `v-html` with DOMPurify-sanitized output. 4. The victim uses Vikunja Desktop and clicks the link. 5. Because no `will-navigate` handler exists, the BrowserWindow navigates to `https://evil.example/exploit` in the same renderer process. 6. The attacker's page now executes in a context with `nodeIntegration: true` and runs: `require('child_process').exec('id > /tmp/pwned');` 7. Arbitrary commands execute as the victim's OS user. ## Impact Full remote code execution on the victim's desktop. The attacker can read/write arbitrary files, execute arbitrary commands, install malware or backdoors, and exfiltrate credentials and sensitive data. No XSS vulnerability is required -- a normal, sanitizer-approved hyperlink is sufficient. ## Proof of concept 1. Set up a Vikunja instance with two users sharing a project. 2. As the attacker user, edit a project description to include: `<a href="https://attacker.example/poc.html">Meeting notes</a>` 3. Host poc.html with: `<script>require('child_process').exec('calc.exe')</script>` 4. As the victim, open the project in Vikunja Desktop and click the link. 5. calc.exe (or any other command) executes on the victim's machine. ## Credits This vulnerability was found using [GitHub Security Lab Taskflows](https://github.com/GitHubSecurityLab/seclab-taskflows).

Vikunja is an open-source self-hosted task management platform. Prior to version 2.2.0, a flaw in Vikunja’s password reset logic allows disabled users to regain access to their accounts. The `ResetPassword()` function sets the user’s status to `StatusActive` after a successful password reset without verifying whether the account was previously disabled. By requesting a reset token through `/api/v1/user/password/token` and completing the reset via `/api/v1/user/password/reset`, a disabled user can reactivate their account and bypass administrator-imposed account disablement. Version 2.2.0 patches the issue.

Vikunja is an open-source self-hosted task management platform. Prior to version 2.2.0, an authenticated user can read any task comment by ID, regardless of whether they have access to the task the comment belongs to, by substituting the task ID in the API URL with a task they do have access to. Version 2.2.0 fixes the issue.

Vikunja is an open-source self-hosted task management platform. Starting in version 0.21.0 and prior to version 2.2.0, the Vikunja Desktop Electron wrapper enables `nodeIntegration` in the renderer process without `contextIsolation` or `sandbox`. This means any cross-site scripting (XSS) vulnerability in the Vikunja web frontend -- present or future -- automatically escalates to full remote code execution on the victim's machine, as injected scripts gain access to Node.js APIs. Version 2.2.0 fixes the issue.

Vikunja is an open-source self-hosted task management platform. Prior to version 2.2.1, the migration helper functions `DownloadFile` and `DownloadFileWithHeaders` in `pkg/modules/migration/helpers.go` make arbitrary HTTP GET requests without any SSRF protection. When a user triggers a Todoist or Trello migration, file attachment URLs from the third-party API response are passed directly to these functions, allowing an attacker to force the Vikunja server to fetch internal network resources and return the response as a downloadable task attachment. Version 2.2.1 patches the issue.

Vikunja is an open-source self-hosted task management platform. Starting in version 0.8 and prior to version 2.2.0, unauthenticated users are able to bypass the application's built-in rate-limits by spoofing the `X-Forwarded-For` or `X-Real-IP` headers due to the rate-limit relying on the value of `(echo.Context).RealIP`. Unauthenticated users can abuse endpoints available to them for different potential impacts. The immediate concern would be brute-forcing usernames or specific accounts' passwords. This bypass allows unlimited requests against unauthenticated endpoints. Version 2.2.0 patches the issue.

Vikunja is an open-source self-hosted task management platform. Starting in version 0.20.2 and prior to version 2.2.0, the `DELETE /api/v1/projects/:project/background` endpoint checks `CanRead` permission instead of `CanUpdate`, allowing any user with read-only access to a project to permanently delete its background image. Version 2.2.0 fixes the issue.

Vikunja is an open-source self-hosted task management platform. Versions prior to 2.1.0 have a business logic vulnerability exists in the password reset mechanism of vikunja/api that allows password reset tokens to be reused indefinitely. Due to a failure to invalidate tokens upon use and a critical logic bug in the token cleanup cron job, reset tokens remain valid forever. This allows an attacker who intercepts a single reset token (via logs, browser history, or phishing) to perform a complete, persistent account takeover at any point in the future, bypassing standard authentication controls. Version 2.1.0 contains a patch for the issue.