# CVE-2021-42083: Authenticated Stored XSS in OSNEXUS QuantaStor 6.0.0.335

> Authenticated attackers can inject malicious scripts via webhook URLs in QuantaStor, leading to remote code execution with root privileges.

- **Severity:** High 8.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Jul 2023
- **Updated:** 22 Sep 2025
- **Also known as:** GHSA-9c8q-55w7-h67h

## What is CVE-2021-42083?

CVE-2021-42083 is a high-severity cross-site scripting vulnerability in OSNEXUS QuantaStor, published on 10 Jul 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

An authenticated attacker is able to create alerts that trigger a stored XSS attack.

POC

  *  go to the alert manager

  *  open the ITSM tab
  *  add a webhook with the URL/service token value 

'	-h	&&	id	|	tee	/tmp/ttttttddddssss	#' (whitespaces are tab characters)

  *  click add

  *  click apply

  *  create a test alert

  *  The test alert will run the command 

“id	|	tee	/tmp/ttttttddddssss” as root.

  *  after the test alert inspect 

/tmp/ttttttddddssss it'll contain the ids of the root user.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2021-42083?

It affects 1 product.


Products: Osnexus Quantastor.

## How do I fix CVE-2021-42083?

No fix has been published for CVE-2021-42083 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42083 being exploited?

There is no known exploitation of CVE-2021-42083 in the wild and no public exploit code.

## Other vulnerabilities in OSNEXUS QuantaStor

- [CVE-2021-42081](https://insights.sbomify.com/CVE-2021-42081/): Authenticated Remote Command Execution vulnerability in OSNEXUS QuantaStor before 6.0.0.355 (critical 9.1)
- [CVE-2021-4406](https://insights.sbomify.com/CVE-2021-4406/): Authenticated Remote COmmand Execution as root in OSNEXUS QuantaStor version 6.0.0.355 and others (critical 9.1)
- [CVE-2021-42082](https://insights.sbomify.com/CVE-2021-42082/): Local Privilege Escalation to root in OSNEXUS QuantaStor before 6.0.0.355 (high 7.8)
- [CVE-2021-42080](https://insights.sbomify.com/CVE-2021-42080/): Reflected XSS vulnerability in OSNEXUS QuantaStor before 6.0.0.355 (high 7.4)
- [CVE-2021-42079](https://insights.sbomify.com/CVE-2021-42079/): SSRF vulnerability in OSNEXUS QuantaStor before 6.0.0.355 (medium 6.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42083 and fix it if it is affected.

What it is: CVE-2021-42083 is a high-severity cross-site scripting vulnerability in OSNEXUS QuantaStor, published on 10 Jul 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-42083 in the wild and no public exploit code.

Affected product: OSNEXUS QuantaStor. 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-2021-42083/ (Markdown: https://insights.sbomify.com/CVE-2021-42083/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42083
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42083
- OSV: https://osv.dev/vulnerability/CVE-2021-42083

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42083/
Summaries are generated and may contain mistakes; the official description above is the record.