# CVE-2018-10561: Dasan GPON Routers Authentication Bypass

> Attackers can bypass authentication on Dasan GPON home routers by appending a specific query string, gaining administrative control over the device.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 31 Mar 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 May 2018
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-9f5c-v3c9-rfhg

## What is CVE-2018-10561?

CVE-2018-10561 is a critical authentication bypass vulnerability in n/a, published on 4 May 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered on Dasan GPON home routers. It is possible to bypass authentication simply by appending "?images" to any URL of the device that requires authentication, as demonstrated by the /menu.html?images/ or /GponForm/diag_FORM?images/ URI. One can then manage the device.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2018-10561?

It affects 1 product.


Products: Dasannetworks Gpon Router Firmware.

## How do I fix CVE-2018-10561?

No fix has been published for CVE-2018-10561 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 21 Apr 2022.

## Is CVE-2018-10561 being exploited?

Yes. Attackers have exploited CVE-2018-10561 in the wild since at least 31 Mar 2022.

Public exploit code:

- GPON Routers - Authentication Bypass / Command Injection (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2018-10562](https://insights.sbomify.com/CVE-2018-10562/): Dasan GPON Routers Command Injection (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-10561 and fix it if it is affected.

What it is: CVE-2018-10561 is a critical authentication bypass vulnerability in n/a, published on 4 May 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2018-10561 in the wild since at least 31 Mar 2022.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2018-10561/ (Markdown: https://insights.sbomify.com/CVE-2018-10561/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-10561
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-10561
- OSV: https://osv.dev/vulnerability/CVE-2018-10561

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-10561/
Summaries are generated and may contain mistakes; the official description above is the record.