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.
What this means for your business
- An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 19% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
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Scoring
- CVSS
- 7.1 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N- Weakness
- CWE-639
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-08-28
- Last modified
- 2026-09-09
- Sources
- NVD