# CVE-2021-28936: Auth bypass in n/a

> An unauthenticated attacker can change the administrator password via a crafted HTTP GET request, gaining full control of the device.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Mar 2021
- **Updated:** 9 Jul 2026
- **Also known as:** GHSA-4mx8-3m5q-284r

## What is CVE-2021-28936?

CVE-2021-28936 is a high-severity authentication bypass vulnerability in n/a, published on 29 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Acexy Wireless-N WiFi Repeater REV 1.0 (28.08.06.1) Web management administrator password can be changed by sending a specially crafted HTTP GET request. The administrator username has to be known (default:admin) whereas no previous authentication is required.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2021-28936?

It affects 1 product.


Products: Acexy Wireless-N Wifi Repeater Firmware.

## How do I fix CVE-2021-28936?

No fix has been published for CVE-2021-28936 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-28936 being exploited?

There is no known exploitation of CVE-2021-28936 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-28937](https://insights.sbomify.com/CVE-2021-28937/): Information disclosure in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-28936 and fix it if it is affected.

What it is: CVE-2021-28936 is a high-severity authentication bypass vulnerability in n/a, published on 29 Mar 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-2021-28936 in the wild and no public exploit code.

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-2021-28936/ (Markdown: https://insights.sbomify.com/CVE-2021-28936/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-28936
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-28936
- OSV: https://osv.dev/vulnerability/CVE-2021-28936

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-28936/
Summaries are generated and may contain mistakes; the official description above is the record.