# CVE-2021-21571: Security feature bypass in UEFI BIOS https stack

> Remote attackers can bypass certificate validation in Dell BIOS HTTPS features via MITM, causing denial of service and payload tampering.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 24 Jun 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-g784-x97g-r6ww

## What is CVE-2021-21571?

CVE-2021-21571 is a medium-severity vulnerability in Dell Chengming 3990 Firmware, published on 24 Jun 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Dell UEFI BIOS https stack leveraged by the Dell BIOSConnect feature and Dell HTTPS Boot feature contains an improper certificate validation vulnerability. A remote unauthenticated attacker may exploit this vulnerability using a person-in-the-middle attack which may lead to a denial of service and payload tampering.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2021-21571?

It affects 128 products.


Products: Dell Alienware M15 R6 Firmware, Dell Chengming 3990 Firmware, Dell Chengming 3991 Firmware, Dell G15 5510 Firmware, Dell G15 5511 Firmware, Dell G3 3500 Firmware, Dell G5 5500 Firmware, Dell G7 7500 Firmware, Dell G7 7700 Firmware, Dell Inspiron 14 5418 Firmware, Dell Inspiron 15 5518 Firmware, Dell Inspiron 15 7510 Firmware, Dell Inspiron 3501 Firmware, Dell Inspiron 3880 Firmware, Dell Inspiron 3881 Firmware, Dell Inspiron 3891 Firmware, Dell Inspiron 5300 Firmware, Dell Inspiron 5301 Firmware, Dell Inspiron 5310 Firmware, Dell Inspiron 5400 2-in-1 Firmware and 108 more.

## How do I fix CVE-2021-21571?

No fix has been published for CVE-2021-21571 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21571 being exploited?

There is no known exploitation of CVE-2021-21571 in the wild and no public exploit code.

## Other vulnerabilities in Dell Chengming 3990 Firmware

- [CVE-2024-52541](https://insights.sbomify.com/CVE-2024-52541/): Auth bypass in Dell Client Platform BIOS (high 8.2)
- [CVE-2022-26861](https://insights.sbomify.com/CVE-2022-26861/): Code injection in CPG BIOS (high 7.9)
- [CVE-2022-34403](https://insights.sbomify.com/CVE-2022-34403/): Memory corruption in CPG BIOS (high 7.5)
- [CVE-2022-26860](https://insights.sbomify.com/CVE-2022-26860/): Memory corruption in CPG BIOS (high 7.5)
- [CVE-2021-21572](https://insights.sbomify.com/CVE-2021-21572/): Memory corruption in BIOSConnect (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21571 and fix it if it is affected.

What it is: CVE-2021-21571 is a medium-severity vulnerability in Dell Chengming 3990 Firmware, published on 24 Jun 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-21571 in the wild and no public exploit code.

Affected product: Dell Chengming 3990 Firmware. 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-2021-21571/ (Markdown: https://insights.sbomify.com/CVE-2021-21571/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21571
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21571
- OSV: https://osv.dev/vulnerability/CVE-2021-21571

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-21571/
Summaries are generated and may contain mistakes; the official description above is the record.