CVE-2026-91981

Vikunja before 2.6.0 User Enumeration via v2 API

Published Sep 15, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-vfxw-3x8p-2vjr Vikunja: Link-share token can enumerate users through the v2 API
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Vikunja before 2.6.0 User Enumeration via v2 API
First Time appeared Vikunja
Vikunja vikunja
Weaknesses CWE-200
CPEs cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:*
Vendors & Products Vikunja
Vikunja vikunja
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Sep 21, 2026, 6:47 PM
Reserved
Sep 15, 2026, 11:10 AM
Status
Deferred
Published
Sep 15, 2026, 4:17 PM
Modified
Sep 21, 2026, 7:17 PM