CVE-2026-55064

Description

Vikunja is an open-source self-hosted task management platform. From 2.3.0 until 2.4.0, a user with Write but not Admin permission on a shared child project can detach it from its parent hierarchy by submitting parent_project_id equal to 0 to POST /api/v1/projects/{project}. The Project.CanUpdate authorization check in pkg/models/project_permissions.go and UpdateProject logic in pkg/models/project.go only gate nonzero parent values, while UpdateProject always persists parent_project_id, so the explicit zero value bypasses the Admin requirement introduced for CVE-2026-35595. Detachment severs the recursive permission-inheritance chain and can disrupt the owner’s hierarchy and inherited collaborator access. This issue is fixed in version 2.4.0.

CVSS Vector

References

• https://github.com/go-vikunja/vikunja/commit/781ffac198548ae4f3d1febc613caed8e0e11d01
• https://github.com/go-vikunja/vikunja/pull/3239
• https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0
• https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4
• https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4