# CVE-2026-33678: Vikunja has IDOR in Task Attachment ReadOne Allows Cross-Project File Access and Deletion

> Authenticated users can access or delete attachments from other projects by manipulating attachment IDs, bypassing task-level permission checks.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A: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:** 24 Mar 2026
- **Updated:** 24 Mar 2026
- **Also known as:** GHSA-jfmm-mjcp-8wq2, GO-2026-4853

## What is CVE-2026-33678?

CVE-2026-33678 is a high-severity missing authorization vulnerability in go-vikunja vikunja, published on 24 Mar 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. Prior to version 2.2.1, `TaskAttachment.ReadOne()` queries attachments by ID only (`WHERE id = ?`), ignoring the task ID from the URL path. The permission check in `CanRead()` validates access to the task specified in the URL, but `ReadOne()` loads a different attachment that may belong to a task in another project. This allows any authenticated user to download or delete any attachment in the system by providing their own accessible task ID with a target attachment ID. Attachment IDs are sequential integers, making enumeration trivial. Version 2.2.1 patches the issue.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-33678?

3 open source packages ship an affected version, including code.vikunja.io/api. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `code.vikunja.io/api` | Go | All versions | None |
| `code.vikunja.io/api` | Go | All versions | 2.2.1 |
| `code.vikunja.io/api` | Go | All versions | 2.2.1 |

Products: Vikunja Vikunja.

## How do I fix CVE-2026-33678?

Upgrade code.vikunja.io/api to 2.2.1 or later.

## Is CVE-2026-33678 being exploited?

There is no known exploitation of CVE-2026-33678 in the wild and no public exploit code.

## Other vulnerabilities in go-vikunja vikunja

- [CVE-2026-28268](https://insights.sbomify.com/CVE-2026-28268/): Vikunja Vulnerable to Account Takeover via Password Reset Token Reuse (critical 9.8)
- [CVE-2026-27575](https://insights.sbomify.com/CVE-2026-27575/): Vijkunja has Weak Password Policy Combined with Persistent Sessions After Password Change (critical 9.1)
- [CVE-2026-25935](https://insights.sbomify.com/CVE-2026-25935/): Vikunja Affected by XSS Via Task Preview (high 8.6)
- [CVE-2026-35595](https://insights.sbomify.com/CVE-2026-35595/): Vikunja Affected by Privilege Escalation via Project Reparenting (high 8.3)
- [CVE-2026-33316](https://insights.sbomify.com/CVE-2026-33316/): Vikunja’s Improper Access Control Enables Bypass of Administrator-Imposed Account Disablement (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33678 and fix it if it is affected.

What it is: CVE-2026-33678 is a high-severity missing authorization vulnerability in go-vikunja vikunja, published on 24 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-33678 in the wild and no public exploit code.

Affected packages and fixed versions:
- code.vikunja.io/api (Go): affected all versions; no fix listed
- code.vikunja.io/api (Go): affected all versions; fixed in 2.2.1
- code.vikunja.io/api (Go): affected all versions; fixed in 2.2.1

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-2026-33678/ (Markdown: https://insights.sbomify.com/CVE-2026-33678/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33678
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33678
- OSV: https://osv.dev/vulnerability/CVE-2026-33678

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33678/
Summaries are generated and may contain mistakes; the official description above is the record.