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.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
go-vikunja vikunja unaffected
Version Status Constraints
0 affected < 2.6.0
2.6.0 unaffected —

No data.

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Project Subscriptions

Vendors Products
Vikunja Subscribe
Vikunja Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/go-vikunja/vikunja/security/advisories/GHSA-vfxw-3x8p-2vjr cve-icon cve-icon
https://www.vulncheck.com/advisories/vikunja-before-2.6.0-user-enumeration-via-v2-api cve-icon cve-icon
History

Tue, 15 Sep 2026 15:30:00 +0000

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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-15T15:18:25.523Z

Reserved: 2026-09-15T11:10:41.353Z

Link: CVE-2026-91981

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-15T16:17:55.087

Modified: 2026-09-15T16:17:55.087

Link: CVE-2026-91981

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses