# CVE-2026-123506: Vikunja 2.2.0 before 2.7.1 Token Scope Bypass via Project Webhook Endpoints

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

Vikunja from 2.2.0 before 2.7.1 contains an authorization bypass vulnerability that allows holders of tokens scoped only to projects_webhooks to manage the owner's user-level webhooks by supplying user_id in request bodies. Attackers can register user webhooks to their own receiver to obtain reminders and task payloads from all owner projects, and read, change or delete existing user webhooks.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- go-vikunja / vikunja (code.vikunja.io/api): ≥ 2.2.0; < 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:L/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.4 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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:L/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: 5.4 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.21% as of 2026-11-09; percentile 10.64%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-863

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-5f6v-j6xm-wwj9 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/vikunja-2.2.0-before-2.7.1-token-scope-bypass-via-project-webhook-endpoints (CNA: VulnCheck; third-party-advisory)

- https://github.com/go-vikunja/vikunja/security/advisories/GHSA-5f6v-j6xm-wwj9 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/vikunja-2.2.0-before-2.7.1-token-scope-bypass-via-project-webhook-endpoints (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123506; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123506; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123506; retrieved 2026-11-09; source updated Not reported

Revision: 648b0cc1025063bcc41f9e7d2f743e9acee3d9f47d4bbc268014ab7995287383

Canonical: https://y2.dev/cve/CVE-2026-123506

## 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.