# CVE-2026-107804: Nginx UI: Bundled reverse proxy can bypass IP allowlists and enable shared login lockout

> Attackers can bypass IP allowlists and trigger shared login lockouts in Nginx UI by exploiting missing trusted proxy configuration in the bundled reverse proxy.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Oct 2026
- **Updated:** 9 Oct 2026
- **Also known as:** GHSA-9h23-53f4-q947, GO-2026-6724

## What is CVE-2026-107804?

CVE-2026-107804 is a medium-severity vulnerability in 0xJacky nginx-ui, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-346 (Origin Validation Error)

## Which versions are affected by CVE-2026-107804?

3 open source packages ship an affected version, including github.com/0xJacky/Nginx-UI.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/0xJacky/Nginx-UI` | Go | All versions | 1.9.10-0.20260904075558-e30e331303fc |
| `github.com/0xJacky/Nginx-UI` | Go | From 1.9.10-0.20251005005631-6de168c9454 | 1.9.10-0.20260904075558-e30e331303fc |
| `github.com/0xJacky/Nginx-UI` | Go | From 1.9.10-0.20251005005631-6de168c9454 | 1.9.10-0.20260904075558-e30e331303fc |

## How do I fix CVE-2026-107804?

Upgrade github.com/0xJacky/Nginx-UI to 1.9.10-0.20260904075558-e30e331303fc or later.

## Is CVE-2026-107804 being exploited?

There is no known exploitation of CVE-2026-107804 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107804 and fix it if it is affected.

What it is: CVE-2026-107804 is a medium-severity vulnerability in 0xJacky nginx-ui, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-107804 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/0xJacky/Nginx-UI (Go): affected all versions; fixed in 1.9.10-0.20260904075558-e30e331303fc
- github.com/0xJacky/Nginx-UI (Go): affected from 1.9.10-0.20251005005631-6de168c9454; fixed in 1.9.10-0.20260904075558-e30e331303fc
- github.com/0xJacky/Nginx-UI (Go): affected from 1.9.10-0.20251005005631-6de168c9454; fixed in 1.9.10-0.20260904075558-e30e331303fc

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-107804/ (Markdown: https://insights.sbomify.com/CVE-2026-107804/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107804
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107804
- OSV: https://osv.dev/vulnerability/CVE-2026-107804

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107804/
Summaries are generated and may contain mistakes; the official description above is the record.