Vulnerability · Published Sep 15, 2026 · Assigned by VulnCheck
CVE-2026-91981Vikunja before 2.6.0 User Enumeration via v2 API
Medium 4.3
In plain English
A medium-severity information exposure in vikunja from go-vikunja. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.3%top 76.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | code.vikunja.io/api | 2.6.0 | GHSA-vfxw-3x8p-2vjr |
| Go | code.vikunja.io/api | no fix listed | GO-2026-6752 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| go-vikunja | vikunja | 0 – before 2.6.0 |
Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
References
- GitHub Security Advisory (GHSA-vfxw-3x8p-2vjr) vendor-advisory
- VulnCheck Advisory: Vikunja before 2.6.0 User Enumeration via v2 API third-party-advisory