A user with only a single self-owned project can permanently destroy the Kanban bucket assignments (task_buckets) and task ordering (task_positions) of any other project view in the entire instance. The ProjectView.Delete model method runs three SQL statements: the first is properly scoped to (view_id, project_id), but the next two cascading deletes on task_buckets and task_positions filter only on the URL-supplied project_view_id. The permission check (CanDelete) gates on Admin of the …
POST /api/v1/projects/{project}/views/{view}/buckets/{bucket} mass-assigns the request body's project_view_id onto the bucket row. The permission check only verifies that the URL-supplied bucket already belongs to the URL-supplied (project, view) pair; the body's project_view_id is never validated. Any signed-in user can therefore take one of their own buckets and graft it into any other tenant's kanban view, with attacker-controlled title and the attacker's account as created_by. This vulnerability was found using an LLM, …
The kanban endpoint POST /api/v1/projects/{project}/views/{view}/buckets/{bucket}/tasks moves a task into a bucket. The task is identified by task_id in the request body. The endpoint's authorization check (TaskBucket.CanUpdate) only verifies that the caller may update the project/view/bucket named in the URL — it never checks any permission on task_id. Any authenticated user can therefore supply another user's task ID (task IDs are a global, sequential integer space) against a kanban bucket in …
The fix for CVE-2026-35595 (project re-parenting privilege escalation) only gates reparent operations when parent_project_id > 0. A user with Write (but not Admin) permission on a shared child project can detach it from its parent by sending parent_project_id: 0, bypassing the Admin requirement. This severs the recursive CTE permission inheritance chain, potentially disrupting the project hierarchy and affecting inherited access for other collaborators.
The project-duplication endpoint fails to enforce write access to the target parent project. Any authenticated (non-link-share) user can duplicate a project they can read into any parent project on the instance, regardless of whether they have write access to that parent — injecting an attacker-owned project into another user's or team's project hierarchy.
Vikunja's scoped API token enforcement for custom project background routes is method-confused. A token with only projects.background can successfully delete a project background, while a token with only projects.background_delete is rejected. This is a scoped-token authorization bypass.
Vikunja's link share authentication constructs authorization objects entirely from JWT claims without any server-side database validation. When a project owner deletes a link share or downgrades its permissions, all previously issued JWTs continue to grant the original permission level for up to 72 hours (the default service.jwtttl). GetLinkShareFromClaims at pkg/models/link_sharing.go lines 88-119 performs zero database queries — it builds the LinkSharing struct purely from JWT claim values (id, hash, project_id, …
The TOTP failed-attempt lockout mechanism is non-functional due to a database transaction handling bug. The account lock is written to the same database session that the login handler always rolls back on TOTP failure, so the lockout is triggered but never persisted. This allows unlimited brute-force attempts against TOTP codes.
A user with Write-level access to a project can escalate their permissions to Admin by moving the project under a project they own. After reparenting, the recursive permission CTE resolves ownership of the new parent as Admin on the moved project. The attacker can then delete the project, manage shares, and remove other users' access.
The CalDAV GetResource and GetResourcesByList methods fetch tasks by UID from the database without verifying that the authenticated user has access to the task's project. Any authenticated CalDAV user who knows (or guesses) a task UID can read the full task data from any project on the instance.
The OIDC callback handler issues a full JWT token without checking whether the matched user has TOTP two-factor authentication enabled. When a local user with TOTP enrolled is matched via the OIDC email fallback mechanism, the second factor is completely skipped.
The CalDAV output generator builds iCalendar VTODO entries via raw string concatenation without applying RFC 5545 TEXT value escaping. User-controlled task titles containing CRLF characters break the iCalendar property boundary, allowing injection of arbitrary iCalendar properties such as ATTACH, VALARM, or ORGANIZER.
Task titles are embedded directly into Markdown link syntax in overdue email notifications without escaping Markdown special characters. When rendered by goldmark and sanitized by bluemonday (which allows <a> and <img> tags), injected Markdown constructs produce phishing links and tracking pixels in legitimate notification emails.
The Vikunja file import endpoint uses the attacker-controlled Size field from the JSON metadata inside the import zip instead of the actual decompressed file content length for the file size enforcement check. By setting Size to 0 in the JSON while including large compressed file entries in the zip, an attacker bypasses the configured maximum file size limit.
The hasAccessToLabel function contains a SQL operator precedence bug that allows any authenticated user to read any label that has at least one task association, regardless of project access. Label titles, descriptions, colors, and creator information are exposed.
The addRepeatIntervalToTime function uses an O(n) loop that advances a date by the task's RepeatAfter duration until it exceeds the current time. By creating a repeating task with a 1-second interval and a due date far in the past, an attacker triggers billions of loop iterations, consuming CPU and holding a database connection for minutes per request.
Two independently-exploitable authorization flaws in Vikunja can be chained to allow an unauthenticated attacker to download and delete every file attachment across all projects in a Vikunja instance. The ReadAll endpoint for link shares exposes share hashes (including admin-level shares) to any user with read access, enabling permission escalation. The task attachment ReadOne/GetTaskAttachment endpoint performs permission checks against a user-supplied task ID but fetches the attachment by its own sequential …
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.
When the Vikunja API returns tasks, it populates the related_tasks field with full task objects for all related tasks without checking whether the requesting user has read permission on those tasks' projects. An authenticated user who can read a task that has cross-project relations will receive full details (title, description, due dates, priority, percent completion, project ID, etc.) of tasks in projects they have no access to.
The DELETE /api/v1/projects/:project/shares/:share endpoint does not verify that the link share belongs to the project specified in the URL. An attacker with admin access to any project can delete link shares from other projects by providing their own project ID combined with the target share ID.
When a user account is disabled or locked, the status check is only enforced on the local login and JWT token refresh paths. Three other authentication paths — API tokens, CalDAV basic auth, and OpenID Connect — do not verify user status, allowing disabled or locked users to continue accessing the API and syncing data.
The GET /api/v1/projects/:project/webhooks endpoint returns webhook BasicAuth credentials (basic_auth_user and basic_auth_password) in plaintext to any user with read access to the project. While the existing code correctly masks the HMAC secret field, the BasicAuth fields added in a later migration were not given the same treatment. This allows read-only collaborators to steal credentials intended for authenticating against external webhook receivers.
The LinkSharing.ReadAll() method allows link share authenticated users to list all link shares for a project, including their secret hashes. While LinkSharing.CanRead() correctly blocks link share users from reading individual shares via ReadOne, the ReadAllWeb handler bypasses this check by never calling CanRead(). An attacker with a read-only link share can retrieve hashes for write or admin link shares on the same project and authenticate with them, escalating to full …
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 …
The DownloadImage function in pkg/utils/avatar.go uses a bare http.Client{} with no SSRF protection when downloading user avatar images from the OpenID Connect picture claim URL. An attacker who controls their OIDC profile picture URL can force the Vikunja server to make HTTP GET requests to arbitrary internal or cloud metadata endpoints. This bypasses the SSRF protections that are correctly applied to the webhook system.
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.
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.
Any user that has enabled 2FA can have their TOTP reused during the standard 30 second validity window.
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.
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.
The Caldav endpoint allows login using Basic Authentication, which in turn allows users to bypass the TOTP on 2FA-enabled accounts. The user can then access standard project information that would normally be protected behind 2FA (if enabled), such as project name, description, etc.
Vulnerability: Unbounded image decoding and resizing during preview generation lets an attacker exhaust CPU and memory with highly compressed but extremely large-dimension images. Affected code: Decoding without bounds: task_attachment.go:GetPreview Resizing path: resizeImage Endpoint invoking preview: GetTaskAttachment Impact: First preview generation per attachment can allocate large memory and spend significant CPU; multiple attachments or concurrent requests can degrade or crash the service. CVSS v3.1: 7.5 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Summary A critical 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 …
Path Traversal (Zip Slip) and Denial of Service (DoS) vulnerability discovered in the Vikunja CLI's restore functionality.
Details The application allows users to upload SVG files as task attachments. SVG is an XML-based format that supports JavaScript execution through elements such as tags or event handlers like onload. The application does not sanitize SVG content before storing it. When the uploaded SVG file is accessed via its direct URL, it is rendered inline in the browser under the application's origin. As a result, embedded JavaScript executes in …
Vikunja is an open-source self-hosted task management platform with 3,300+ GitHub stars. A reflected HTML injection vulnerability exists in the Projects module where the filter URL parameter is rendered into the DOM without output encoding when the user clicks "Filter." While <script> and <iframe> are blocked, <svg>, <a>, and formatting tags (<h1>, <b>, <u>) render without restriction — enabling SVG-based phishing buttons, external redirect links, and content spoofing within the …
Summary The application allows users to set weak passwords (e.g., 1234, password) without enforcing minimum strength requirements. Additionally, active sessions remain valid after a user changes their password. An attacker who compromises an account (via brute-force or credential stuffing) can maintain persistent access even after the victim resets their password. Details Weak passwords are accepted during registration and password change. No minimum length or strength validation is enforced. After changing …
The task preview component creates a unparented div. The div's innerHtml is set to the unescaped description of the task