# CVE-2021-21998: Auth bypass in VMware Carbon Black App Control (AppC)

> An attacker with network access can bypass authentication to gain administrative control of the VMware Carbon Black App Control management server.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-fp4q-hrv9-r6f5

## What is CVE-2021-21998?

CVE-2021-21998 is a critical authentication bypass vulnerability in VMware Carbon Black App Control (AppC), published on 23 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

VMware Carbon Black App Control 8.0, 8.1, 8.5 prior to 8.5.8, and 8.6 prior to 8.6.2 has an authentication bypass. A malicious actor with network access to the VMware Carbon Black App Control management server might be able to obtain administrative access to the product without the need to authenticate.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-21998?

It affects 1 product.


Products: Vmware Carbon Black App Control.

## How do I fix CVE-2021-21998?

No fix has been published for CVE-2021-21998 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21998 being exploited?

There is no known exploitation of CVE-2021-21998 in the wild and no public exploit code.

## Other vulnerabilities in VMware Carbon Black App Control (AppC)

- [CVE-2022-22951](https://insights.sbomify.com/CVE-2022-22951/): Command injection in VMware Carbon Black App Control (AppC) (critical 9.1)
- [CVE-2022-22952](https://insights.sbomify.com/CVE-2022-22952/): File upload in VMware Carbon Black App Control (AppC) (critical 9.1)
- [CVE-2023-20858](https://insights.sbomify.com/CVE-2023-20858/): Code injection in VMware Carbon Black App Control (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21998 and fix it if it is affected.

What it is: CVE-2021-21998 is a critical authentication bypass vulnerability in VMware Carbon Black App Control (AppC), published on 23 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-21998 in the wild and no public exploit code.

Affected product: VMware Carbon Black App Control (AppC). 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-2021-21998/ (Markdown: https://insights.sbomify.com/CVE-2021-21998/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21998
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21998
- OSV: https://osv.dev/vulnerability/CVE-2021-21998

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21998/
Summaries are generated and may contain mistakes; the official description above is the record.