# CVE-2021-27856: FatPipe software administrative account with no password

> An administrative account with no password allows attackers to gain full control of FatPipe network software.

- **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:** 15 Dec 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-8235-wx5q-8wrv

## What is CVE-2021-27856?

CVE-2021-27856 is a critical vulnerability in FatPipe IPVPN, published on 15 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FatPipe WARP, IPVPN, and MPVPN software prior to versions 10.1.2r60p91 and 10.2.2r42 includes an account named "cmuser" that has administrative privileges and no password. Older versions of FatPipe software may also be vulnerable. The FatPipe advisory identifier for this vulnerability is FPSA002.

## Which versions are affected by CVE-2021-27856?

It affects 3 products.


Products: Fatpipeinc Ipvpn Firmware, Fatpipeinc Mpvpn Firmware, Fatpipeinc Warp Firmware.

## How do I fix CVE-2021-27856?

No fix has been published for CVE-2021-27856 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27856 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-27856 exists.

Public exploit code:

- FatPipe WARP/IPVPN/MPVPN - Backdoor Account (nuclei): http/cves/2021/CVE-2021-27856.yaml

## Other vulnerabilities in FatPipe IPVPN

- [CVE-2021-27860](https://insights.sbomify.com/CVE-2021-27860/): FatPipe WARP, IPVPN, and MPVPN Configuration Upload exploit (critical 9.8, exploited in the wild)
- [CVE-2021-27855](https://insights.sbomify.com/CVE-2021-27855/): FatPipe software allows privilege escalation (high 8.8)
- [CVE-2021-27859](https://insights.sbomify.com/CVE-2021-27859/): Missing authorization vulnerability in FatPipe software (high 8.8)
- [CVE-2021-27857](https://insights.sbomify.com/CVE-2021-27857/): FatPipe software allows unauthenticated configuration download (high 7.5)
- [CVE-2021-27858](https://insights.sbomify.com/CVE-2021-27858/): Missing authorization vulnerability in FatPipe software (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27856 and fix it if it is affected.

What it is: CVE-2021-27856 is a critical vulnerability in FatPipe IPVPN, published on 15 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-27856 exists.

Affected product: FatPipe IPVPN. 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-2021-27856/ (Markdown: https://insights.sbomify.com/CVE-2021-27856/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27856
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27856
- OSV: https://osv.dev/vulnerability/CVE-2021-27856

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27856/
Summaries are generated and may contain mistakes; the official description above is the record.