{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "2.3.0"
              },
              {
                "fixed": "2.4.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "28b537837f9808dc106c9058b5829c65759fddf2"
            },
            {
              "fixed": "781ffac198548ae4f3d1febc613caed8e0e11d01"
            },
            {
              "fixed": "907850feae3866ae9b16ea1c7b84a4d77273415a"
            }
          ],
          "repo": "https://github.com/go-vikunja/vikunja",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-44v6-7fxq-vgf4"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-862"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55064.json"
  },
  "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.",
  "id": "CVE-2026-55064",
  "modified": "2026-08-30T03:30:53.792307827Z",
  "published": "2026-08-28T16:38:38.293Z",
  "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"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Vikunja incomplete fix for CVE-2026-35595: Write-only user can detach shared project from parent hierarchy via parent_project_id=0"
}