CVE-2026-91981: Go-Vikunja Vikunja

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Vikunja versions before 2.6.0 fail to properly validate link-share tokens in the v2 API user search endpoints. Attackers with a read-only share link can enumerate project users via the projects endpoint and confirm arbitrary usernames exist via the global search endpoint.

Affected products

• Go-Vikunja Vikunja: before 2.6.0 (fixed in 2.6.0)

Published 2026-09-15. Last modified 2026-09-21.