CVE-2026-91980: vikunja before 2.6.0 Team Enumeration via Project Share

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-15 · updated 2026-09-16
Weakness: CWE-200

Description

vikunja before 2.6.0 fails to validate team access when attaching teams to projects, allowing authenticated users to enumerate all teams and members. Attackers can attach arbitrary team IDs via the project teams endpoint to retrieve complete team rosters including member names and admin flags for unauthorized teams.

Affected products

go-vikunja vikunja: before 2.6.0 — fixed in 2.6.0

How to fix

Upgrade to a fixed version: go-vikunja vikunja 2.6.0. Check the vendor advisory for mitigations.

References

https://github.com/go-vikunja/vikunja/security/advisories/GHSA-39p5-2wrr-xh29
https://www.vulncheck.com/advisories/vikunja-before-2.6.0-team-enumeration-via-project-share
https://github.com/go-vikunja/vikunja/security/advisories/GHSA-39p5-2wrr-xh29

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