# CVE-2020-8354: Race condition in BIOS

> A race condition in the Lenovo Notebook BIOS SMI callback allows attackers to execute arbitrary code, requiring firmware updates.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:L/AC:H/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:** 11 Nov 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-g763-g64f-m23g

## What is CVE-2020-8354?

CVE-2020-8354 is a medium-severity vulnerability in Lenovo BIOS, published on 11 Nov 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A potential vulnerability in the SMI callback function used in the VariableServiceSmm driver in some Lenovo Notebook models may allow arbitrary code execution.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2020-8354?

It affects 1 product.


Products: Lenovo Notebook Firmware.

## How do I fix CVE-2020-8354?

No fix has been published for CVE-2020-8354 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-8354 being exploited?

There is no known exploitation of CVE-2020-8354 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8354 and fix it if it is affected.

What it is: CVE-2020-8354 is a medium-severity vulnerability in Lenovo BIOS, published on 11 Nov 2020. 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-2020-8354 in the wild and no public exploit code.

Affected product: Lenovo 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-2020-8354/ (Markdown: https://insights.sbomify.com/CVE-2020-8354/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8354
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8354
- OSV: https://osv.dev/vulnerability/CVE-2020-8354

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-8354/
Summaries are generated and may contain mistakes; the official description above is the record.