Vikunja through 2.4.0 Principal-Type Confusion via LinkSharing

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

• go-vikunja vikunja

  • up to and including 2.4.0affected · semver

Other highest-scoring records for the same primary product.

• CVE-2026-68582Vikunja 0.24.0 Broken Object Level Authorization via Link-Share Token
  37Monitor
• CVE-2026-91985Vikunja before 2.6.0 Privilege Escalation via Link Share Hash
  34Monitor
• CVE-2026-91973Vikunja before 2.6.0 Authentication Bypass via CalDAV BasicAuth
  34Monitor
• CVE-2026-91972Vikunja before 2.6.0 Authentication Bypass via Unthrottled API
  34Monitor
• CVE-2026-68581Vikunja 0.22.0 through 2.3.0 Authentication Bypass via Principal ID Collision
  34Monitor
• CVE-2026-55065Vikunja: Improper Authorization and Authorization Bypass Through User-Controlled Key in code.vikunja.io/api
  32Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

The endpoint fetches the record by the ID sent in the request, but never checks whether the record belongs to the requesting user.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const invoice = await Invoice.findById(req.params.id);2res.json(invoice);

1const invoice = await Invoice.findOne({2  id: req.params.id,3  ownerId: req.user.id,4});5if (!invoice) return res.sendStatus(404);6res.json(invoice);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.