# CVE-2020-8336: Security feature bypass in BIOS

> Attackers can bypass Intel CSME anti-rollback protections on Lenovo ThinkPads, potentially allowing the installation of vulnerable firmware versions.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jun 2020
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-rmxg-p4v2-9f92

## What is CVE-2020-8336?

CVE-2020-8336 is a medium-severity vulnerability in Lenovo BIOS, published on 9 Jun 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Lenovo implemented Intel CSME Anti-rollback ARB protections on some ThinkPad models to prevent roll back of CSME Firmware in flash.

## Which versions are affected by CVE-2020-8336?

It affects 38 products.


Products: Lenovo Thinkpad E14 Firmware, Lenovo Thinkpad E15 Firmware, Lenovo Thinkpad E490 Firmware, Lenovo Thinkpad E490s Firmware, Lenovo Thinkpad E590 Firmware, Lenovo Thinkpad L13 1st Gen Firmware, Lenovo Thinkpad L1415 Gen 1 Firmware, Lenovo Thinkpad L390 Yoga Firmware, Lenovo Thinkpad L490 Firmware, Lenovo Thinkpad L590 Firmware, Lenovo Thinkpad P1 \(20mx\) Firmware, Lenovo Thinkpad P1 \(20qx\) Firmware, Lenovo Thinkpad P43s \(20rx\) Firmware, Lenovo Thinkpad P52 \(20mx\) Firmware, Lenovo Thinkpad P53 \(20qx\) Firmware, Lenovo Thinkpad P53s \(20nx\) Firmware, Lenovo Thinkpad P72 \(20mx\) Firmware, Lenovo Thinkpad P73 \(20qx\) Firmware, Lenovo Thinkpad R14 Firmware, Lenovo Thinkpad R490 Firmware and 18 more.

## How do I fix CVE-2020-8336?

No fix has been published for CVE-2020-8336 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-8336 being exploited?

There is no known exploitation of CVE-2020-8336 in the wild and no public exploit code.

## Other vulnerabilities in Lenovo BIOS

- [CVE-2022-48189](https://insights.sbomify.com/CVE-2022-48189/): Other in ThinkPad BIOS (medium 6.7)
- [CVE-2023-2290](https://insights.sbomify.com/CVE-2023-2290/): Memory corruption in ThinkPad (medium 6.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8336 and fix it if it is affected.

What it is: CVE-2020-8336 is a medium-severity vulnerability in Lenovo BIOS, published on 9 Jun 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-2020-8336 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-2020-8336/ (Markdown: https://insights.sbomify.com/CVE-2020-8336/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8336
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8336
- OSV: https://osv.dev/vulnerability/CVE-2020-8336

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8336/
Summaries are generated and may contain mistakes; the official description above is the record.