Vikunja 1.0.0-rc0 before 2.7.0 Cross-Tenant Task Position Writes via Saved Filter Creation

{
  "id": "4800289f1803df69fd180aa90ea09ee4d9931747f684f751ad9568715f1b3ae8",
  "url": "https://osv.dev/vulnerability/CVE-2026-111918",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Vikunja 1.0.0-rc0 before 2.7.0 Cross-Tenant Task Position Writes via Saved Filter Creation",
    "summary": "Vikunja from 1.0.0-rc0 before 2.7.0 contains an improper authorization vulnerability in RecalculateTaskPositions that allows authenticated users with zero accessible projects to write task_positions rows for all tasks instance-wide. Attackers can delete their Inbox after repointing default_project_id, then create empty-filter saved filters to persist cross-tenant references and amplify writes for denial of service.",
    "evidence": "osv:CVE-2026-111918",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-111918",
      "aliases": [
        "CVE-2026-111918",
        "GHSA-fprf-r6rv-xg99",
        "GO-2026-6731"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/go-vikunja/vikunja",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0a7cc2b7df2d837ae295c748d1e9bf7f1a03dfd5"
                },
                {
                  "fixed": "a16be96aa454671fdf213b0fbe411dd38a098418"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.0.0-rc0"
                      },
                      {
                        "fixed": "2.7.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "1.0.0-rc0"
                      },
                      {
                        "fixed": "2.7.0"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.6.0",
            "v2.5.0",
            "v2.4.0",
            "v2.3.0",
            "v2.2.2",
            "v2.2.1",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0",
            "v1.1.0",
            "v1.0.0",
            "v1.0.0-rc4",
            "v1.0.0-rc3",
            "v1.0.0-rc2",
            "v1.0.0-rc1",
            "v1.0.0-rc0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-111918.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.292429495Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/111xxx/CVE-2026-111918.json",
        "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-fprf-r6rv-xg99",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-111918",
        "https://www.vulncheck.com/advisories/vikunja-1.0.0-rc0-before-2.7.0-cross-tenant-task-position-writes-via-saved-filter-creation"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-863"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/111xxx/CVE-2026-111918.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-111918",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 520009,
  "published_at": "2026-10-17T18:46:33.245+00:00"
}