# CVE-2020-3977: Auth bypass in VMware Horizon DaaS

> An attacker with a legitimate account can bypass two-factor authentication due to a flaw in first factor handling.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Sep 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-564r-7p67-986w

## What is CVE-2020-3977?

CVE-2020-3977 is a medium-severity authentication bypass vulnerability in VMware Horizon DaaS, published on 22 Sep 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

VMware Horizon DaaS (7.x and 8.x before 8.0.1 Update 1) contains a broken authentication vulnerability due to a flaw in the way it handled the first factor authentication. Successful exploitation of this issue may allow an attacker to bypass two-factor authentication process. In order to exploit this issue, an attacker must have a legitimate account on Horizon DaaS.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2020-3977?

It affects 1 product.


Products: Vmware Horizon Daas.

## How do I fix CVE-2020-3977?

No fix has been published for CVE-2020-3977 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3977 being exploited?

There is no known exploitation of CVE-2020-3977 in the wild and no public exploit code.

## Other vulnerabilities in VMware Horizon DaaS

- [CVE-2018-6960](https://insights.sbomify.com/CVE-2018-6960/): Auth bypass in Horizon DaaS (high 8.8)
- [CVE-2017-4897](https://insights.sbomify.com/CVE-2017-4897/): Other in Horizon DaaS (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3977 and fix it if it is affected.

What it is: CVE-2020-3977 is a medium-severity authentication bypass vulnerability in VMware Horizon DaaS, published on 22 Sep 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-3977 in the wild and no public exploit code.

Affected product: VMware Horizon DaaS. 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-2020-3977/ (Markdown: https://insights.sbomify.com/CVE-2020-3977/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3977
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3977
- OSV: https://osv.dev/vulnerability/CVE-2020-3977

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-3977/
Summaries are generated and may contain mistakes; the official description above is the record.