# CVE-2026-35597: Vikunja Affected by TOTP Brute-Force Due to Non-Functional Account Lockout

> Attackers can bypass TOTP account lockout protections to perform unlimited brute-force attacks against user accounts in Vikunja.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Apr 2026
- **Updated:** 13 Apr 2026
- **Also known as:** GHSA-fgfv-pv97-6cmj, GO-2026-5362

## What is CVE-2026-35597?

CVE-2026-35597 is a medium-severity vulnerability in go-vikunja vikunja, published on 10 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Vikunja is an open-source self-hosted task management platform. Prior to 2.3.0, the TOTP failed-attempt lockout mechanism is non-functional due to a database transaction handling bug. When a TOTP validation fails, the login handler in pkg/routes/api/v1/login.go calls HandleFailedTOTPAuth and then unconditionally rolls back. HandleFailedTOTPAuth in pkg/user/totp.go uses an in-memory counter (key-value store) to track failed attempts. When the counter reaches 10, it calls user.SetStatus(s, StatusAccountLocked) on the same database session s. Because the login handler always rolls back after a TOTP failure, the StatusAccountLocked write is undone. The in-memory counter correctly increments past 10, so the lockout code executes on every subsequent attempt, but the database write is rolled back every time. This allows unlimited brute-force attempts against TOTP codes. This vulnerability is fixed in 2.3.0.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2026-35597?

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 | 2.3.0 |
| `code.vikunja.io/api` | Go | All versions | 2.3.0 |

Products: Vikunja Vikunja.

## How do I fix CVE-2026-35597?

Upgrade code.vikunja.io/api to 2.3.0 or later.

## Is CVE-2026-35597 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35597 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-2026-35597 and fix it if it is affected.

What it is: CVE-2026-35597 is a medium-severity vulnerability in go-vikunja vikunja, published on 10 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35597 exists.

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 2.3.0
- code.vikunja.io/api (Go): affected all versions; fixed in 2.3.0

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-2026-35597/ (Markdown: https://insights.sbomify.com/CVE-2026-35597/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35597
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35597
- OSV: https://osv.dev/vulnerability/CVE-2026-35597

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35597/
Summaries are generated and may contain mistakes; the official description above is the record.