# CVE-2021-21730: Auth bypass in ZXHN H168N

> Attackers can brute force credentials to gain unauthorized CLI access on ZTE ZXHN H168N routers, potentially leading to full device control.

- **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:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-9xvw-8r73-2f95

## What is CVE-2021-21730?

CVE-2021-21730 is a critical authentication bypass vulnerability in ZXHN H168N, published on 13 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A ZTE product is impacted by improper access control vulnerability. The attacker could exploit this vulnerability to access CLI by brute force attacks.This affects: ZXHN H168N V3.5.0_TY.T6

## Which versions are affected by CVE-2021-21730?

It affects 1 product.


Products: Zte Zxhn H168n Firmware.

## How do I fix CVE-2021-21730?

No fix has been published for CVE-2021-21730 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21730 being exploited?

There is no known exploitation of CVE-2021-21730 in the wild and no public exploit code.

## Other vulnerabilities in ZXHN H168N

- [CVE-2021-21735](https://insights.sbomify.com/CVE-2021-21735/): Information disclosure in ZXHN H168N (medium 6.5)
- [CVE-2018-7357](https://insights.sbomify.com/CVE-2018-7357/): Missing authorization in ZXHN H168N (medium 6.5)
- [CVE-2018-7358](https://insights.sbomify.com/CVE-2018-7358/): Auth bypass in ZXHN H168N (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21730 and fix it if it is affected.

What it is: CVE-2021-21730 is a critical authentication bypass vulnerability in ZXHN H168N, published on 13 Apr 2021. 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-2021-21730 in the wild and no public exploit code.

Affected product: ZXHN H168N. 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-2021-21730/ (Markdown: https://insights.sbomify.com/CVE-2021-21730/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21730
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21730
- OSV: https://osv.dev/vulnerability/CVE-2021-21730

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21730/
Summaries are generated and may contain mistakes; the official description above is the record.