EUVD-2026-277217

fkie_cve-2026-33473

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.

GHSA-p747-qc5p-773r — Vikunja has TOTP Reuse During Validity Window

Affected: Go: code.vikunja.io/api

### Summary Any user that has enabled 2FA can have their TOTP reused during the standard 30 second validity window.

### Details The below code is called when a user that has 2FA is authenticating to the application. Once they submit a valid username-password-totp combination, the user gets authenticated. If that same TOTP is used for the same user's account again within the validity window, it will allow the other session to authenticate successfully.

**Source**: <ins>pkg/user/totp.go:128</ins> ```go // ValidateTOTPPasscode validated totp codes of users. func ValidateTOTPPasscode(s *xorm.Session, passcode *TOTPPasscode) (t *TOTP, err error) { t, err = GetTOTPForUser(s, passcode.User) if err != nil { return }

if !totp.Validate(passcode.Passcode, t.Secret) { return nil, ErrInvalidTOTPPasscode{Passcode: passcode.Passcode} }

return } ```

Section 6.5.1 within the [Authentication](https://github.com/OWASP/ASVS/blob/master/5.0/en/0x15-V6-Authentication.md) section of the OWASP ASVS recommends multiple checks, some of which involving TOTPs:

> Verify that lookup secrets, out-of-band authentication requests or codes, and time-based one-time passwords (TOTPs) are only successfully usable once.

The OWASP WSTG also references this as one of their [checks](https://owasp.org/www-project-web-security-testing-guide/latest/4-Web_Application_Security_Testing/04-Authentication_Testing/11-Testing_Multi-Factor_Authentication) to look for:

> Can the OTPs be used more than once?…

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EUVD-2026-277217

fkie_cve-2026-33473

GHSA-p747-qc5p-773r — Vikunja has TOTP Reuse During Validity Window