# Vikunja cross-project task disclosure through subtask expansion

Source: https://junglewise.ai/threats/go-2026-6714-vikunja-cross-project-task-disclosure-through-subtask-cba3685c  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-19. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

Severity: info · Published 2026-10-19

Vikunja is a task and project management system that allows tasks to link across projects. When retrieving a project's task list with subtask expansion, the system returns linked subtasks from other projects without checking whether the user has access to those projects. This allows users with read-only access to one project to view full details of tasks in private projects they should not access.

Technologies: [code.vikunja.io/api (Go)](https://junglewise.ai/threats/technologies/code-vikunja-io-api), [Vikunja API](https://junglewise.ai/threats/technologies/vikunja-api). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Vikunja](https://junglewise.ai/threats/vendors/vikunja).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Informational severity, published 19 October 2026.

**Which products and versions are affected?** code.vikunja.io/api (Go) SEMVER:introduced=0; Vikunja API before 2.6.0.

**Is there a fix for This vulnerability?** Yes: fixed in 2.6.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run code.vikunja.io/api (Go) or Vikunja API at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 2.6.0

## Technical details

The vulnerability is a cross-project authorization bypass in the subtask expansion endpoint. When a task list is retrieved with the subtask expansion parameter (?expand[]=subtasks), the API applies access control filtering to the main task list but fails to apply the same filtering when recursively fetching linked subtasks from other projects. An authenticated user with low privilege access to one project can exploit this to read arbitrary task data (title, description, dates, assignees, labels, attachment metadata) from any private project containing a subtask linked under a task they can see.

## Affected products

- Vikunja API before 2.6.0

## Identifiers

- GHSA-3hc7-r24j-rpwc
- GO-2026-6714

## Timeline

- 2026-08-31: disclosed
- 2026-10-19: advisory

## References

- [https://github.com/go-vikunja/vikunja/security/advisories/GHSA-3hc7-r24j-rpwc](https://github.com/go-vikunja/vikunja/security/advisories/GHSA-3hc7-r24j-rpwc)
- [https://github.com/go-vikunja/vikunja/commit/077dc4de79ce6f1ab59215a2c7bf9b30423685f2](https://github.com/go-vikunja/vikunja/commit/077dc4de79ce6f1ab59215a2c7bf9b30423685f2)

## Related threats

- [Vikunja CalDAV relation creation bypasses authorization](https://junglewise.ai/threats/go-2026-6732-vikunja-caldav-relation-creation-bypasses-taskrelation-65a4724c)
- [Vikunja task relation deletion missing authorization check](https://junglewise.ai/threats/go-2026-6754-vikunja-task-relation-deletion-does-not-check-read-access-9f93429b)
- [Vikunja information disclosure in task assignees endpoint](https://junglewise.ai/threats/go-2026-6723-vikunja-assignee-email-addresses-disclosed-to-read-only-e328c145)
- [Vikunja permissive CORS configuration account takeover](https://junglewise.ai/threats/cve-2026-111922-vikunja-from-2-2-0-before-2-7-0-contains-a-permissive-cors)
- [Vikunja incorrect authorization in link share deletion](https://junglewise.ai/threats/cve-2026-111921-vikunja-0-13-0-before-2-7-0-contains-an-incorrect-authorization)