CVE-2026-91972 [HIGH] – Vikunja versions before 2.6.0 fail to apply rate limiting to /api/v2 public authentication

Vikunja versions before 2.6.0 fail to apply rate limiting to /api/v2 public authentication endpoints including login, register, password-reset, and OAuth token routes. Remote unauthenticated attackers can perform unbounded credential guessing, account enumeration, and password-reset flooding attacks without throttling restrictions.