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

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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

Source terms

CVE Program Terms of Use

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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

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

Oct 9, 2026, 2:49:20 PM (timezone not stated)

Source modified

Oct 9, 2026, 3:09:10 PM (timezone not stated)

Observed here

7 Nov 2026 04:31:33 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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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: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

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

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 15:17:09 UTC

Source modified

9 Oct 2026 16:38:57 UTC

Observed here

25 Oct 2026 05:17:13 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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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: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

## Summary In Nginx UI versions 2.2.0 through 2.5.x, the official bundled reverse-proxy topology did not preserve the external client identity used by Gin. The backend treated the local proxy peer as the client because no trusted proxy was configured, while the proxy supplied the actual address in forwarding headers. ## Impact This has two distinct effects in bundled-proxy deployments: * **IP allowlist enforcement:** management API requests forwarded by the bundled proxy were identified as loopback and could pass the loopback exception even when the external source was not in the configured allowlist. Protected management operations still required valid credentials; this did not grant unauthenticated administrator access. * **Login availability:** failed login attempts from different external sources were attributed to one loopback address. An unauthenticated attacker could therefore trigger the shared temporary login-ban threshold and deny password or OTP login to other users behind the proxy until the ban expired. Existing authenticated sessions were not invalidated. ## Remediation Upgrade to Nginx UI 2.6.0 or later. The fix explicitly trusts only the intended bundled proxy, validates configured trusted proxies, uses the resolved client address consistently, and fails closed when an IP allowlist is enabled but the client address is invalid. Fix commit: https://github.com/0xJacky/nginx-ui/commit/e30e331303fc21cf077a2bea724bd79e66892eaf

Source published

9 Oct 2026 20:57:05 UTC

Source modified

19 Oct 2026 21:41:02 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_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Publisher rating · MODERATE

Nginx UI: Bundled reverse proxy can bypass IP allowlists and enable shared login lockout in github.com/0xJacky/Nginx-UI. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: .

Source published

19 Oct 2026 21:08:26 UTC

Source modified

19 Oct 2026 21:31:35 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.