Vikunja has a project duplication bypasses write-permission check on the target parent project

Exploitation

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

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N · score source

EPSS

• CVE-2026-54766: 0.43% estimated exploitation activity in the next 30 days; percentile 37.05 (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 The project-duplication endpoint fails to enforce write access to the target parent project. Any authenticated (non-link-share) user can duplicate a project they can read into any parent project on the instance, regardless of whether they have write access to that parent — injecting an attacker-owned project into another user's or team's project hierarchy. Details ProjectDuplicate.CanCreate (pkg/models/projectduplicate.go) is meant to require write access to the parent the duplicate is placed under — its own comment says "Parent project exists + user has write access". The implementation does neither correctly: Two defects compound here: 1. Wrong permission method. It calls parent.CanCreate ("may I create this project?") instead of parent.CanWrite ("may I create children inside this project?"). The latter is what the normal create path uses — POST /projects with a parentprojectid enforces parent.CanWrite via Project.CanCreate (pkg/models/projectpermissions.go:196-199). 2.…

Published by the source

28 Aug 2026, 16:37 UTC

Last modified by the source

2 Sep 2026, 19:45 UTC

Source last checked

26 Oct 2026, 15:28 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-f27p-pw2p-9pr4

2. Revision 3 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6311

4. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-f27p-pw2p-9pr4

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# Patch Next advisory brief: CVE-2026-54766

Advisory: Vikunja has a project duplication bypasses write-permission check on the target parent project
IDs: CVE-2026-54766, GHSA-f27p-pw2p-9pr4
Record: https://patchnext.com/advisories/cve-2026-54766 (revision 4, 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 5.3)
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 >= 0.21.0, <= 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-f27p-pw2p-9pr4 (OSV record GHSA-f27p-pw2p-9pr4 lists affected ranges: Go code.vikunja.io/api >=0.21.0 <2.4.0 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6311 (OSV record GO-2026-6311 lists affected ranges: Go code.vikunja.io/api >=0.21.0)
- Verified: https://github.com/advisories/GHSA-f27p-pw2p-9pr4 (GitHub-reviewed advisory GHSA-f27p-pw2p-9pr4 lists affected ranges: Go code.vikunja.io/api >=0.21.0 <=2.3.0)

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