# CVE-2021-3718: Denial of service in ThinkPad BIOS

> Attackers can crash Lenovo ThinkPad systems by exploiting a flaw in the Enhanced Biometrics BIOS setting, requiring a firmware update.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 Nov 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-cf28-3crv-xv77

## What is CVE-2021-3718?

CVE-2021-3718 is a medium-severity denial of service vulnerability in Lenovo ThinkPad BIOS, published on 12 Nov 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A denial of service vulnerability was reported in some ThinkPad models that could cause a system to crash when the Enhanced Biometrics setting is enabled in BIOS.

Weakness: CWE-232 (Improper Handling of Undefined Values)

## Which versions are affected by CVE-2021-3718?

It affects 39 products.


Products: Lenovo Thinkpad 11e 3rd Gen Firmware, Lenovo Thinkpad 11e 4th Gen Celeron Firmware, Lenovo Thinkpad 11e 4th Gen I3 Firmware, Lenovo Thinkpad 11e 4th Gen I5 Firmware, Lenovo Thinkpad 11e 4th Gen I7 Firmware, Lenovo Thinkpad 11e 5th Gen Firmware, Lenovo Thinkpad 11e Yoga Gen 6 Firmware, Lenovo Thinkpad 13 Gen 2 Firmware, Lenovo Thinkpad E490 Firmware, Lenovo Thinkpad E490s Firmware, Lenovo Thinkpad E590 Firmware, Lenovo Thinkpad L13 Firmware, Lenovo Thinkpad L13 Gen 2 Firmware, Lenovo Thinkpad L13 Yoga Firmware, Lenovo Thinkpad L13 Yoga Gen 2 Firmware, Lenovo Thinkpad L14 Firmware, Lenovo Thinkpad L14 Gen 1 Firmware, Lenovo Thinkpad L15 Firmware, Lenovo Thinkpad L15 Gen 1 Firmware, Lenovo Thinkpad L380 Firmware and 19 more.

## How do I fix CVE-2021-3718?

No fix has been published for CVE-2021-3718 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3718 being exploited?

There is no known exploitation of CVE-2021-3718 in the wild and no public exploit code.

## Other vulnerabilities in Lenovo ThinkPad BIOS

- [CVE-2021-3843](https://insights.sbomify.com/CVE-2021-3843/): Code injection in ThinkPad BIOS (medium 6.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3718 and fix it if it is affected.

What it is: CVE-2021-3718 is a medium-severity denial of service vulnerability in Lenovo ThinkPad BIOS, published on 12 Nov 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-3718 in the wild and no public exploit code.

Affected product: Lenovo ThinkPad 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-2021-3718/ (Markdown: https://insights.sbomify.com/CVE-2021-3718/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3718
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3718
- OSV: https://osv.dev/vulnerability/CVE-2021-3718

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-3718/
Summaries are generated and may contain mistakes; the official description above is the record.