Vikunja: Explicit lower-permission share on a sub-project is silently overridden by an inherited parent permission (broken access control / privilege-management regression in v2.6.0)

Exploitation

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

CVSS

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

EPSS

• CVE-2026-111920: 0.19% estimated exploitation activity in the next 30 days; percentile 8.84 (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.

Description

Summary In Vikunja v2.6.0 the project-permission engine resolves a user's effective permission on a project as the MAX over the entire reachable project subtree. As a result, when a user has been granted a higher permission on a parent project and the owner *explicitly* shares a child project with that same user at a lower permission (an intended down-restriction), the explicit lower grant is silently ignored and the user receives the higher, inherited permission on the child. A user who was deliberately restricted to read-only on a sensitive sub-project can therefore modify it, delete it, and re-share it (including granting other users admin) - none of which the owner intended. This is a behavior regression from v2.5.0, whose engine used "nearest-ancestor-grant-wins" semantics that honored the explicit child grant.

Details Effective permissions are computed by a single recursive CTE in `pkg/models/project_access.go`…

Published by the source

9 Oct 2026, 20:57 UTC

Last modified by the source

28 Oct 2026, 15:30 UTC

Source last checked

29 Oct 2026, 06:45 UTC

1. Revision 5 · amended · 29 Oct 2026

   Amended from osv record GHSA-pjr3-86v4-5p7w

2. Revision 4 · amended · 28 Oct 2026

   Amended from ghsa record GHSA-pjr3-86v4-5p7w

3. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-pjr3-86v4-5p7w

4. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6745

5. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-pjr3-86v4-5p7w

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-111920

Advisory: Vikunja: Explicit lower-permission share on a sub-project is silently overridden by an inherited parent permission (broken access control / privilege-management regression in v2.6.0)
IDs: CVE-2026-111920, GHSA-pjr3-86v4-5p7w
Record: https://patchnext.com/advisories/cve-2026-111920 (revision 5, source checked 29 Oct 2026, 06:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
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 2.7.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.vikunja.io/api: affected >= 2.6.0, < 2.7.0; fixed in 2.7.0

## 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/GO-2026-6745 (OSV record GO-2026-6745 lists affected ranges: Go code.vikunja.io/api >=0)
- Verified: https://osv.dev/vulnerability/GHSA-pjr3-86v4-5p7w (OSV record GHSA-pjr3-86v4-5p7w lists affected ranges: Go code.vikunja.io/api >=2.6.0 <=2.6.0)
- Verified: https://github.com/advisories/GHSA-pjr3-86v4-5p7w (GitHub-reviewed advisory GHSA-pjr3-86v4-5p7w lists affected ranges: Go code.vikunja.io/api >=2.6.0 <=2.6.0)
- Verified: https://osv.dev/vulnerability/GHSA-pjr3-86v4-5p7w (OSV record GHSA-pjr3-86v4-5p7w lists affected ranges: Go code.vikunja.io/api >=2.6.0 <2.7.0 (fixed))

Commands are suggestions: review each one before running it.