Information disclosure in Go-Vikunja Vikunja
CVE-2026-91981
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.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/go-vikunja/vikunja/security/advisories/GHSA-vfxw-3x8p-2vjr (vendor-advisory)
- www.vulncheck.com/advisories/vikunja-before-2.6.0-user-enumeration-via-v2-api (third-party-advisory)
Frequently asked questions
- What is CVE-2026-91981?
- CVE-2026-91981 is a medium-severity vulnerability in Go-Vikunja Vikunja, classified under Information Disclosure. CVSS score: 4.3/10. Published 2026-09-15.
- How severe is CVE-2026-91981?
- Medium severity. CVSS v3 base score is 4.3 out of 10.