# CVE-2021-27952: Hardcoded credentials in n/a

> Hardcoded root credentials allow attackers to access the bootloader via serial console, enabling privilege escalation and potential code execution on ecobee3 lite devices.

- **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:** 3 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-3xpf-gg8x-9h3c

## What is CVE-2021-27952?

CVE-2021-27952 is a critical 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

Hardcoded default root credentials exist on the ecobee3 lite 4.5.81.200 device. This allows a threat actor to gain access to the password-protected bootloader environment through the serial console.

Weakness: CWE-798 (Use of Hard-coded Credentials)

## Which versions are affected by CVE-2021-27952?

It affects 1 product.


Products: Ecobee Ecobee3 Lite Firmware.

## How do I fix CVE-2021-27952?

No fix has been published for CVE-2021-27952 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27952 being exploited?

There is no known exploitation of CVE-2021-27952 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-27954](https://insights.sbomify.com/CVE-2021-27954/): Memory corruption in n/a (high 8.2)
- [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-2021-27952 and fix it if it is affected.

What it is: CVE-2021-27952 is a critical 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-2021-27952 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-2021-27952/ (Markdown: https://insights.sbomify.com/CVE-2021-27952/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27952
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27952
- OSV: https://osv.dev/vulnerability/CVE-2021-27952

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27952/
Summaries are generated and may contain mistakes; the official description above is the record.