Vikunja before 2.6.0 contains an API token scope bypass vulnerability in task read endpoints where authorization fails to inspect query string parameters. Attackers with limited token scopes can use the expand parameter to access restricted data like comments, reactions, and time entries without proper permission verification.

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.

Exploitation poc

Automatable no

Technical Impact partial

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
1.0.0 affected < 2.6.0
2.6.0 unaffected —

No data.

No data.

No data.

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-9rg3-v78m-26q8 cve-icon cve-icon cve-icon
https://www.vulncheck.com/advisories/vikunja-before-2.6.0-api-token-scope-bypass-via-expand-parameter cve-icon cve-icon
History

Tue, 15 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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

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

Type Values Removed Values Added
Description Vikunja before 2.6.0 contains an API token scope bypass vulnerability in task read endpoints where authorization fails to inspect query string parameters. Attackers with limited token scopes can use the expand parameter to access restricted data like comments, reactions, and time entries without proper permission verification.
Title Vikunja before 2.6.0 API Token Scope Bypass via expand Parameter
First Time appeared Vikunja
Vikunja vikunja
Weaknesses CWE-863
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: 2026-09-15T15:52:07.941Z

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

Link: CVE-2026-91983

cve-icon Vulnrichment

Updated: 2026-09-15T15:52:03.479Z

cve-icon NVD

Status : Received

Published: 2026-09-15T16:17:55.373

Modified: 2026-09-15T16:17:55.373

Link: CVE-2026-91983

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses