Vikunja is an open-source self-hosted task management platform. Starting in version 0.8 and prior to version 2.2.0, unauthenticated users are able to bypass the application's built-in rate-limits by spoofing the `X-Forwarded-For` or `X-Real-IP` headers due to the rate-limit relying on the value of `(echo.Context).RealIP`. Unauthenticated users can abuse endpoints available to them for different potential impacts. The immediate concern would be brute-forcing usernames or specific accounts' passwords. This bypass allows unlimited requests against unauthenticated endpoints. Version 2.2.0 patches the issue.
https://vikunja.io/changelog/vikunja-v2.2.0-was-released
https://github.com/go-vikunja/vikunja/security/advisories/GHSA-m547-hp4w-j6jx