Nginx UI: Bundled reverse proxy can bypass IP allowlists and enable shared login lockout

Nginx UI is a web user interface for the Nginx web server. From 2.2.0 until 2.6.0, the bundled reverse proxy does not preserve the external client identity used by Gin because the backend has no trusted proxy configuration. Management requests can be attributed to loopback and pass the IP allowlist loopback exception, although valid credentials are still required. Failed logins from different external clients are also attributed to the same loopback address, allowing an unauthenticated attacker to trigger a shared temporary login ban for password or OTP authentication without invalidating existing sessions. This issue is fixed in version 2.6.0.

Source published

9 Oct 2026 14:49:20 UTC

Source modified

9 Oct 2026 15:09:10 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L