Auth bypass in Go-Vikunja Vikunja
CVE-2026-76216
Vikunja through 2.4.0 contains a principal-type confusion vulnerability where LinkSharing principals with id N are treated as user principals with users.id == N at three permission checks lacking type guards. Attackers with a link-share JWT can remove victims from teams, enumerate and delete victim bot users, or read team rosters by exploiting id collisions in the autoincrement space.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (27.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.8% 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: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/go-vikunja/vikunja/security/advisories/GHSA-32r8-5843-4qw2 (vendor-advisory)
- www.vulncheck.com/advisories/vikunja-through-principal-type-confusion-via-links… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-76216?
- CVE-2026-76216 is a high-severity vulnerability in Go-Vikunja Vikunja, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 7.5/10. Published 2026-08-19.
- How severe is CVE-2026-76216?
- High severity. CVSS v3 base score is 7.5 out of 10.