Vikunja before 2.6.0 fails to properly restrict access to the link-share hash field in single-share read endpoints, allowing read-only members to obtain the share's secret credential. Attackers can exchange the disclosed hash for a link-share JWT at the share's permission level to escalate privileges and perform unauthorized writes or administrative actions.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

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 None

Scope Unchanged

Confidentiality Impact High

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 yes

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
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-qfwc-vx6f-3g6g cve-icon cve-icon cve-icon
https://www.vulncheck.com/advisories/vikunja-before-2.6.0-privilege-escalation-via-link-share-hash cve-icon cve-icon
History

Tue, 15 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', '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 fails to properly restrict access to the link-share hash field in single-share read endpoints, allowing read-only members to obtain the share's secret credential. Attackers can exchange the disclosed hash for a link-share JWT at the share's permission level to escalate privileges and perform unauthorized writes or administrative actions.
Title Vikunja before 2.6.0 Privilege Escalation via Link Share Hash
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': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-15T16:04:15.007Z

Reserved: 2026-09-15T11:10:41.354Z

Link: CVE-2026-91985

cve-icon Vulnrichment

Updated: 2026-09-15T16:03:58.847Z

cve-icon NVD

Status : Received

Published: 2026-09-15T16:17:57.010

Modified: 2026-09-15T17:17:44.127

Link: CVE-2026-91985

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses