# CVE-2021-27954: Memory corruption in n/a

> A heap-based buffer overflow in the ecobee3 lite HomeKit setup allows attackers to force SSID connections or cause denial of service.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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:** 3 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-gm95-7c28-qmq3

## What is CVE-2021-27954?

CVE-2021-27954 is a high-severity memory corruption vulnerability in n/a, published on 3 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A heap-based buffer overflow vulnerability exists on the ecobee3 lite 4.5.81.200 device in the HKProcessConfig function of the HomeKit Wireless Access Control setup process. A threat actor can exploit this vulnerability to force the device to connect to a SSID or cause a denial of service.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-27954?

It affects 1 product.


Products: Ecobee Ecobee3 Lite Firmware.

## How do I fix CVE-2021-27954?

No fix has been published for CVE-2021-27954 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27954 being exploited?

There is no known exploitation of CVE-2021-27954 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-27952](https://insights.sbomify.com/CVE-2021-27952/): Hardcoded credentials in n/a (critical 9.8)
- [CVE-2021-27953](https://insights.sbomify.com/CVE-2021-27953/): Null dereference in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27954 and fix it if it is affected.

What it is: CVE-2021-27954 is a high-severity memory corruption vulnerability in n/a, published on 3 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-2021-27954 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-2021-27954/ (Markdown: https://insights.sbomify.com/CVE-2021-27954/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27954
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27954
- OSV: https://osv.dev/vulnerability/CVE-2021-27954

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27954/
Summaries are generated and may contain mistakes; the official description above is the record.