# CVE-2021-27663: CEM Systems AC2000

> Remote attackers can bypass authorization to access the CEM Systems AC2000 access control system without proper credentials.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/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:** 30 Aug 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-7w94-337p-g84p

## What is CVE-2021-27663?

CVE-2021-27663 is a high-severity missing authorization vulnerability in Johnson Controls CEM Systems AC2000, published on 30 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in versions 10.1 through 10.5 of Johnson Controls CEM Systems AC2000 allows a remote attacker to access to the system without adequate authorization. This issue affects: Johnson Controls CEM Systems AC2000 10.1; 10.2; 10.3; 10.4; 10.5.

Weakness: CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2021-27663?

It affects 1 product.


Products: Johnsoncontrols Ac2000 Firmware.

## How do I fix CVE-2021-27663?

No fix has been published for CVE-2021-27663 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27663 being exploited?

There is no known exploitation of CVE-2021-27663 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27663 and fix it if it is affected.

What it is: CVE-2021-27663 is a high-severity missing authorization vulnerability in Johnson Controls CEM Systems AC2000, published on 30 Aug 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-2021-27663 in the wild and no public exploit code.

Affected product: Johnson Controls CEM Systems AC2000. 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-2021-27663/ (Markdown: https://insights.sbomify.com/CVE-2021-27663/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27663
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27663
- OSV: https://osv.dev/vulnerability/CVE-2021-27663

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-27663/
Summaries are generated and may contain mistakes; the official description above is the record.