Vikunja vulnerable to authenticated cross-tenant kanban-bucket relocation via project_view_id mass-assignment

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.0 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N

EPSS

• CVE-2026-55067: 0.34% estimated exploitation activity in the next 30 days; percentile 27.07 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary POST /api/v1/projects/{project}/views/{view}/buckets/{bucket} mass-assigns the request body's projectviewid onto the bucket row. The permission check only verifies that the URL-supplied bucket already belongs to the URL-supplied (project, view) pair; the body's projectviewid is never validated. Any signed-in user can therefore take one of their own buckets and graft it into any other tenant's kanban view, with attacker-controlled title and the attacker's account as createdby. This vulnerability was found using an LLM, and manually verified against latest (2.3.0). Vulnerable code pkg/models/kanban.go (lines 348-359): Bucket.CanUpdate (canDoBucket) only validates that the URL-supplied {bucket} belongs to the URL-supplied {project}/{view}. The body's projectviewid reaches Update unchecked and is written through. Proof of Concept Prerequisites: Two registered users (attacker and victim). In the IDs below: attacker's project is 2, kanban view 8; victim's project is 1, kanban view…

Published by the source

28 Aug 2026, 16:55 UTC

Last modified by the source

2 Sep 2026, 19:30 UTC

Source last checked

26 Oct 2026, 15:28 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-569v-q83c-3j3g

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6307

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-569v-q83c-3j3g

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# Patch Next advisory brief: CVE-2026-55067

Advisory: Vikunja vulnerable to authenticated cross-tenant kanban-bucket relocation via `project_view_id` mass-assignment
IDs: CVE-2026-55067, GHSA-569v-q83c-3j3g
Record: https://patchnext.com/advisories/cve-2026-55067 (revision 3, source checked 26 Oct 2026, 15:28 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: code.vikunja.io/api 2.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.vikunja.io/api: affected <= 2.3.0; fixed in 2.4.0

## Suggested inspection (read-only)
- Go code.vikunja.io/api: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on code.vikunja.io/api.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-569v-q83c-3j3g (OSV record GHSA-569v-q83c-3j3g lists affected ranges: Go code.vikunja.io/api >=0 <2.4.0 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6307 (OSV record GO-2026-6307 lists affected ranges: Go code.vikunja.io/api >=0)
- Verified: https://github.com/advisories/GHSA-569v-q83c-3j3g (GitHub-reviewed advisory GHSA-569v-q83c-3j3g lists affected ranges: Go code.vikunja.io/api >=0 <=2.3.0)

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