Auth bypass in Go-Vikunja Vikunja
CVE-2026-55066
Vikunja is an open-source self-hosted task management platform. Prior to 2.4.0, POST /api/v1/projects/{project}/views/{view}/buckets/{bucket}/tasks accepts a body supplied task_id but TaskBucket.CanUpdate in pkg/models/kanban_task_bucket.go authorizes only the project, view, and bucket from the URL. updateTaskBucket then calls Task.ReadOne without a separate task permission check, returns the victim task contents, and can update the task done state when the attacker chooses a done bucket. Because task identifiers are global sequential values, an authenticated user can enumerate cross-tenant tasks and modify their completion metadata through both the v1 and v2 routes that share this model. This issue is fixed in version 2.4.0.
Vulnerability class: IDOR (Insecure Direct Object Reference)
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N.
Affected products
- Go-vikunja Vikunja — versions < 2.4.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-55066?
- CVE-2026-55066 is a high-severity vulnerability in Go-Vikunja Vikunja, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 7.1/10. Published 2026-08-28.
- How severe is CVE-2026-55066?
- High severity. CVSS v3 base score is 7.1 out of 10.