CVE-2026-91985

Vikunja before 2.6.0 Privilege Escalation via Link Share Hash

Published Sep 15, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-qfwc-vx6f-3g6g Vikunja: Read-only project members can obtain any link share's access hash via the single-share read endpoint (v1 and v2) and escalate to the share's permission level
History
Type Values Removed Values Added
First Time appeared Go-vikunja
Go-vikunja vikunja
Vendors & Products Go-vikunja
Go-vikunja vikunja
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Sep 15, 2026, 4:04 PM
Reserved
Sep 15, 2026, 11:10 AM
Status
Deferred
Published
Sep 15, 2026, 4:17 PM
Modified
Sep 16, 2026, 7:49 PM