What’s Vulnerable › Vulnerabilities

CVE-2026-55064: Vikunja incomplete fix for CVE-2026-35595: Write-only user can detach shared project from parent hierarchy via parent_project_id=0

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-28 · updated 2026-09-09
• Weakness: CWE-862

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.

Affected products

• go-vikunja vikunja: from 2.3.0, < 2.4.0

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

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