Vikunja: Every /api/v2 pre-auth endpoint is unthrottled on a stock install while its /api/v1 twin is rate limited

### Summary `registerAPIRoutesV2` never applies the unconditional pre-auth rate-limit floor (`unauthRateLimit()`) to the v2 public routes — it passes that limiter only to `/api/v2/ws` — and otherwise relies on `setupRateLimit`, which registers nothing when `ratelimit.enabled` is false (the default). So on a stock install every v2 pre-auth endpoint (login, register, password-reset token, oauth token) is unthrottled, while its v1 twin is throttled. ### Details `unauthRateLimit()` -> `perMinuteIPRateLimit("noauth", RateLimitNoAuthRoutesLimit)` (`pkg/routes/rate_limit.go`, ~lines 100-118) is an unconditional per-IP floor (default 10/60s) that deliberately ignores `RateLimitEnabled`, which is why v1's pre-auth routes are throttled even with the global limiter off. v1 applies it: `ur := a.Group(""); ur.Use(unauthRateLimit())` (`pkg/routes/routes.go` ~line 459). `registerAPIRoutesV2` (~lines 405-431) passes the `unauthRateLimit()` instance only to `/api/v2/ws`; its auth routes get only `setupRateLimit(a, ...)`, which is config-gated and registers nothing by default. ### PoC (verified at runtime against v2.5.0) ``` POST /api/v1/login x25 -> 429 from attempt 5 POST /api/v2/login x25 -> 403 x25, 429 x0 POST /api/v1/user/password/token -> 429 (throttled) POST /api/v2/user/password/token x20 -> 404 x20, 429 x0 ``` Request bodies are byte-identical across versions (shared `user.Login` / `user.PasswordTokenRequest`). Both v2 endpoints reach their handlers (403/404, not route-404), so the comparison is valid. ### Impact The pre-auth rate-limit floor — the instance's only default anti-brute-force / anti-abuse control — is absent on all v2 public endpoints. Enables unbounded credential guessing, account-enumeration probing, and password-reset flooding on a default install. Reported as an authentication-control bypass, not a DoS. ### Fix Apply `unauthRateLimit()` to the v2 public route group, matching v1.

Source published

9 Oct 2026 20:51:05 UTC

Source modified

19 Oct 2026 21:41:17 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Publisher rating · HIGH