# CVE-2026-33473: Vikunja has TOTP Reuse During Validity Window

> Attackers can reuse TOTP codes within the validity window to bypass two-factor authentication and take over user accounts.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 24 Mar 2026
- **Updated:** 24 Mar 2026
- **Also known as:** GHSA-p747-qc5p-773r, GO-2026-4805

## What is CVE-2026-33473?

CVE-2026-33473 is a medium-severity authentication bypass vulnerability in go-vikunja vikunja, published on 24 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Vikunja is an open-source self-hosted task management platform. Starting in version 0.13 and prior to version 2.2.1, any user that has enabled 2FA can have their TOTP reused during the standard 30 second validity window. Version 2.2.1 patches the issue.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-33473?

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 | From 0.13 | None |
| `code.vikunja.io/api` | Go | From 0.13 | None |

Products: Vikunja Vikunja.

## How do I fix CVE-2026-33473?

Upgrade to a fixed version.

## Is CVE-2026-33473 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33473 exists.

## 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-2026-33473 and fix it if it is affected.

What it is: CVE-2026-33473 is a medium-severity authentication bypass vulnerability in go-vikunja vikunja, published on 24 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33473 exists.

Affected packages and fixed versions:
- code.vikunja.io/api (Go): affected all versions; no fix listed
- code.vikunja.io/api (Go): affected from 0.13; no fix listed
- code.vikunja.io/api (Go): affected from 0.13; no fix listed

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-2026-33473/ (Markdown: https://insights.sbomify.com/CVE-2026-33473/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33473
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33473
- OSV: https://osv.dev/vulnerability/CVE-2026-33473

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33473/
Summaries are generated and may contain mistakes; the official description above is the record.