# CVE-2026-54766: Vikunja: Project duplication bypasses write-permission check on the target parent project

> Authenticated users can bypass write-permission checks to inject content into arbitrary project hierarchies during project duplication.

- **Severity:** Medium 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** GHSA-f27p-pw2p-9pr4, GO-2026-6311

## What is CVE-2026-54766?

CVE-2026-54766 is a medium-severity missing authorization vulnerability in go-vikunja vikunja, published on 28 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Vikunja is an open-source self-hosted task management platform. From 0.21.0 until 2.4.0, the project duplication operation in pkg/models/project_duplicate.go allows an authenticated user who can read a source project to place its duplicate beneath an arbitrary target parent project. ProjectDuplicate.CanCreate calls parent.CanCreate on an unhydrated Project containing only the body supplied parent_project_id instead of calling parent.CanWrite, so the target parent write-permission check is skipped. The ordinary project creation path enforces that permission, but PUT /api/v1/projects/{project}/duplicate does not, allowing attacker-owned content to be injected into another user or team project hierarchy. This issue is fixed in version 2.4.0.

Weakness: CWE-863 (Incorrect Authorization), CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2026-54766?

3 open source packages ship an affected version, including code.vikunja.io/api.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `code.vikunja.io/api` | Go | From 0.21.0 | None |
| `code.vikunja.io/api` | Go | From 0.21.0 | 2.4.0 |
| `code.vikunja.io/api` | Go | From 0.21.0 | 2.4.0 |

## How do I fix CVE-2026-54766?

Upgrade code.vikunja.io/api to 2.4.0 or later.

## Is CVE-2026-54766 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54766 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54766 and fix it if it is affected.

What it is: CVE-2026-54766 is a medium-severity missing authorization vulnerability in go-vikunja vikunja, published on 28 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54766 exists.

Affected packages and fixed versions:
- code.vikunja.io/api (Go): affected from 0.21.0; no fix listed
- code.vikunja.io/api (Go): affected from 0.21.0; fixed in 2.4.0
- code.vikunja.io/api (Go): affected from 0.21.0; fixed in 2.4.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-54766/ (Markdown: https://insights.sbomify.com/CVE-2026-54766/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54766
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54766
- OSV: https://osv.dev/vulnerability/CVE-2026-54766

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54766/
Summaries are generated and may contain mistakes; the official description above is the record.