# CVE-2021-21559: Security feature bypass in NetWorker

> An unauthenticated attacker can perform man-in-the-middle attacks to intercept and tamper with traffic between the NetWorker client and server due to improper certificate validation.

- **Severity:** High 7.1 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** No
- **Published:** 8 Jun 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-jqfx-r8vc-qw5m

## What is CVE-2021-21559?

CVE-2021-21559 is a high-severity vulnerability in Dell NetWorker, published on 8 Jun 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Dell EMC NetWorker, versions 18.x, 19.1.x, 19.2.x 19.3.x, 19.4, and 19.4.0.1 contain an Improper Certificate Validation vulnerability in the client (NetWorker Management Console) components which uses SSL encrypted connection in order to communicate with the application server. An unauthenticated attacker in the same network collision domain as the NetWorker Management Console client could potentially exploit this vulnerability to perform man-in-the-middle attacks to intercept and tamper the traffic between the client and the application server.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2021-21559?

It affects 1 product.


Products: Dell Emc Networker.

## How do I fix CVE-2021-21559?

No fix has been published for CVE-2021-21559 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21559 being exploited?

There is no known exploitation of CVE-2021-21559 in the wild and no public exploit code.

## Other vulnerabilities in Dell NetWorker

- [CVE-2017-8023](https://insights.sbomify.com/CVE-2017-8023/): EMC Networker Remote Code Execution Vulnerability (critical 9.8)
- [CVE-2018-11050](https://insights.sbomify.com/CVE-2018-11050/): Information disclosure in Networker (high 8.8)
- [CVE-2021-21558](https://insights.sbomify.com/CVE-2021-21558/): Information disclosure in NetWorker (high 8.2)
- [CVE-2021-21546](https://insights.sbomify.com/CVE-2021-21546/): Information disclosure in NetWorker (high 7.8)
- [CVE-2023-24567](https://insights.sbomify.com/CVE-2023-24567/): Information disclosure in Dell NetWorker, NVE (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21559 and fix it if it is affected.

What it is: CVE-2021-21559 is a high-severity vulnerability in Dell NetWorker, published on 8 Jun 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-21559 in the wild and no public exploit code.

Affected product: Dell NetWorker. 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-2021-21559/ (Markdown: https://insights.sbomify.com/CVE-2021-21559/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21559
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21559
- OSV: https://osv.dev/vulnerability/CVE-2021-21559

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21559/
Summaries are generated and may contain mistakes; the official description above is the record.