# CVE-2021-3971: Privilege escalation in Notebook BIOS

> An attacker with elevated privileges can modify firmware protection regions via NVRAM variables in Lenovo Notebook BIOS due to a leftover manufacturing driver.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Apr 2022
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-v9mm-m35w-j8fm

## What is CVE-2021-3971?

CVE-2021-3971 is a medium-severity vulnerability in Lenovo Notebook BIOS, published on 22 Apr 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A potential vulnerability by a driver used during older manufacturing processes on some consumer Lenovo Notebook devices that was mistakenly included in the BIOS image could allow an attacker with elevated privileges to modify firmware protection region by modifying an NVRAM variable.

Weakness: CWE-489 (Active Debug Code)

## Which versions are affected by CVE-2021-3971?

It affects 73 products.


Products: Lenovo Ideapad 3-14ada05 Firmware, Lenovo Ideapad 3-14ada6 Firmware, Lenovo Ideapad 3-14alc6 Firmware, Lenovo Ideapad 3-14are05 Firmware, Lenovo Ideapad 3-14igl05 Firmware, Lenovo Ideapad 3-14iil05 Firmware, Lenovo Ideapad 3-15ada05 Firmware, Lenovo Ideapad 3-15ada6 Firmware, Lenovo Ideapad 3-15alc6 Firmware, Lenovo Ideapad 3-15are05 Firmware, Lenovo Ideapad 3-15igl05 Firmware, Lenovo Ideapad 3-15iil05 Firmware, Lenovo Ideapad 3-17ada05 Firmware, Lenovo Ideapad 3-17ada6 Firmware, Lenovo Ideapad 3-17alc6 Firmware, Lenovo Ideapad 3-17are05 Firmware, Lenovo Ideapad 3-17iil05 Firmware, Lenovo Ideapad 5-15are05 Firmware, Lenovo Ideapad Creator 5-15imh05 Firmware, Lenovo Ideapad Gaming 3-15arh05 Firmware and 53 more.

## How do I fix CVE-2021-3971?

No fix has been published for CVE-2021-3971 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3971 being exploited?

There is no known exploitation of CVE-2021-3971 in the wild and no public exploit code.

## Other vulnerabilities in Lenovo Notebook BIOS

- [CVE-2021-3970](https://insights.sbomify.com/CVE-2021-3970/): Code injection in Notebook BIOS (medium 6.7)
- [CVE-2021-3972](https://insights.sbomify.com/CVE-2021-3972/): Security feature bypass in Notebook BIOS (medium 6.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3971 and fix it if it is affected.

What it is: CVE-2021-3971 is a medium-severity vulnerability in Lenovo Notebook BIOS, published on 22 Apr 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3971 in the wild and no public exploit code.

Affected product: Lenovo Notebook BIOS. 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-2021-3971/ (Markdown: https://insights.sbomify.com/CVE-2021-3971/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3971
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3971
- OSV: https://osv.dev/vulnerability/CVE-2021-3971

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3971/
Summaries are generated and may contain mistakes; the official description above is the record.