{"id":"CVE-2026-55064","summary":"Vikunja incomplete fix for CVE-2026-35595: Write-only user can detach shared project from parent hierarchy via parent_project_id=0","details":"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.","aliases":["GHSA-44v6-7fxq-vgf4"],"modified":"2026-08-30T03:46:43.108504475Z","published":"2026-08-28T16:38:38.293Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55064.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-862"]},"references":[{"type":"WEB","url":"https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55064.json"},{"type":"ADVISORY","url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55064"},{"type":"FIX","url":"https://github.com/go-vikunja/vikunja/commit/781ffac198548ae4f3d1febc613caed8e0e11d01"},{"type":"FIX","url":"https://github.com/go-vikunja/vikunja/pull/3239"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/go-vikunja/vikunja","events":[{"introduced":"28b537837f9808dc106c9058b5829c65759fddf2"},{"fixed":"781ffac198548ae4f3d1febc613caed8e0e11d01"},{"fixed":"907850feae3866ae9b16ea1c7b84a4d77273415a"}],"database_specific":{"extracted_events":[{"introduced":"2.3.0"},{"fixed":"2.4.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v2.3.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55064.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"}]}