# CVE-2026-123518: Vikunja before 2.7.1 Missing Authorization in Kanban Task-Bucket Move

Status: published. Published: 2026-11-08. Updated: 2026-11-09.

Vikunja before 2.7.1 contains an incorrect authorization vulnerability in TaskBucket.CanUpdate, which checks write access to the bucket's project and to the task separately but never verifies that both belong to the same project. Authenticated users with write access to two projects can move a task into another project's kanban bucket. This persists cross-project task_buckets rows that count toward bucket limits and, for done buckets, toggle the task's done state.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- go-vikunja / vikunja (code.vikunja.io/api): ≥ 0; < 2.7.1 (affected, semver); 2.7.1 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 5.3 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 4.3 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 5.3 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 4.3 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.19% as of 2026-11-09; percentile 8.92%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-639

## Exploit evidence

- exploit: https://github.com/go-vikunja/vikunja/security/advisories/GHSA-w64q-7p4m-j8g8 (ADP: CISA-ADP)

## References

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-w64q-7p4m-j8g8 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/vikunja-before-2.7.1-missing-authorization-in-kanban-task-bucket-move (CNA: VulnCheck; third-party-advisory)

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-w64q-7p4m-j8g8 (ADP: CISA-ADP; exploit)

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-w64q-7p4m-j8g8 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/vikunja-before-2.7.1-missing-authorization-in-kanban-task-bucket-move (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123518; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123518; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123518; retrieved 2026-11-09; source updated Not reported

Revision: 28871a59eddadabbd85cd83a29874a69372810360de6fa5fc42473e1d563549a

Canonical: https://y2.dev/cve/CVE-2026-123518

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.