# CVE-2021-41823: Cross-site scripting in n/a

> An XSS protection bypass in Kemp LoadMaster WAF allows attackers to execute scripts via onmouseover events, requiring a software upgrade.

- **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:** 1 Jan 2023
- **Updated:** 11 Apr 2025
- **Also known as:** GHSA-8q3m-vc4w-chfw

## What is CVE-2021-41823?

CVE-2021-41823 is a medium-severity cross-site scripting vulnerability in n/a, published on 1 Jan 2023. 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

The Web Application Firewall (WAF) in Kemp LoadMaster 7.2.54.1 allows certain uses of onmouseover to bypass an XSS protection mechanism.

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

## Which versions are affected by CVE-2021-41823?

It affects 1 product.


Products: Kemptechnologies Web Application Firewall.

## How do I fix CVE-2021-41823?

No fix has been published for CVE-2021-41823 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-41823 being exploited?

There is no known exploitation of CVE-2021-41823 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2017-15524](https://insights.sbomify.com/CVE-2017-15524/): Security feature bypass in n/a (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41823 and fix it if it is affected.

What it is: CVE-2021-41823 is a medium-severity cross-site scripting vulnerability in n/a, published on 1 Jan 2023. 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-2021-41823 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-2021-41823/ (Markdown: https://insights.sbomify.com/CVE-2021-41823/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41823
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41823
- OSV: https://osv.dev/vulnerability/CVE-2021-41823

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41823/
Summaries are generated and may contain mistakes; the official description above is the record.