# CVE-2021-35489: Cross-site scripting in n/a

> Reflected XSS in Thruk allows attackers to inject JavaScript via host or service parameters, potentially compromising authenticated user sessions.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **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:** 9 Nov 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-6642-wv2w-7c29

## What is CVE-2021-35489?

CVE-2021-35489 is a medium-severity cross-site scripting vulnerability in n/a, published on 9 Nov 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

Thruk 2.40-2 allows /thruk/#cgi-bin/extinfo.cgi?type=2&host={HOSTNAME]&service={SERVICENAME]&backend={BACKEND] Reflected XSS via the host or service parameter. An attacker could inject arbitrary JavaScript into extinfo.cgi. The malicious payload would be triggered every time an authenticated user browses the page containing it.

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

## Which versions are affected by CVE-2021-35489?

It affects 1 product.


Products: Thruk Thruk.

## How do I fix CVE-2021-35489?

No fix has been published for CVE-2021-35489 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-35489 being exploited?

There is no known exploitation of CVE-2021-35489 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2023-34096](https://insights.sbomify.com/CVE-2023-34096/): Thruk has Path Traversal Vulnerability in panorama.pm (medium 6.5)
- [CVE-2021-35488](https://insights.sbomify.com/CVE-2021-35488/): Cross-site scripting in n/a (medium 6.1)
- [CVE-2024-23822](https://insights.sbomify.com/CVE-2024-23822/): Thruk Incorrect limitation of a pathname to a restricted directory (Path Traversal) (CWE-22) (medium 5.4)
- [CVE-2021-35490](https://insights.sbomify.com/CVE-2021-35490/): Cross-site scripting in n/a (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-35489 and fix it if it is affected.

What it is: CVE-2021-35489 is a medium-severity cross-site scripting vulnerability in n/a, published on 9 Nov 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-2021-35489 in the wild and no public exploit code.

Affected product: n/a. 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-2021-35489/ (Markdown: https://insights.sbomify.com/CVE-2021-35489/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-35489
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-35489
- OSV: https://osv.dev/vulnerability/CVE-2021-35489

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-35489/
Summaries are generated and may contain mistakes; the official description above is the record.