# CVE-2021-40541: Cross-site scripting in n/a

> An authenticated user can trigger cross-site scripting in PHPFusion by appending double slashes to text, potentially leading to session hijacking or malicious script execution.

- **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:** 11 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-gr69-fgwp-qxq8

## What is CVE-2021-40541?

CVE-2021-40541 is a medium-severity cross-site scripting vulnerability in n/a, published on 11 Oct 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

PHPFusion 9.03.110 is affected by cross-site scripting (XSS) in the preg patterns filter html tag without "//" in descript() function An authenticated user can trigger XSS by appending "//" in the end of text.

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

## Which versions are affected by CVE-2021-40541?

It affects 1 product.


Products: Php-Fusion Phpfusion.

## How do I fix CVE-2021-40541?

No fix has been published for CVE-2021-40541 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-40541 being exploited?

There is no known exploitation of CVE-2021-40541 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2022-3152](https://insights.sbomify.com/CVE-2022-3152/): Unverified Password Change in phpfusion/phpfusion (critical 9.6)
- [CVE-2020-23754](https://insights.sbomify.com/CVE-2020-23754/): Cross-site scripting in n/a (critical 9.6)
- [CVE-2023-2453](https://insights.sbomify.com/CVE-2023-2453/): Local file Inclusion (LFI) in Forum Infusion via Directory Traversal (high 8.8)
- [CVE-2020-37137](https://insights.sbomify.com/CVE-2020-37137/): PHP-Fusion 9.03.50 - 'panels.php' Eval Injection (high 8.6)
- [CVE-2021-40188](https://insights.sbomify.com/CVE-2021-40188/): File upload in n/a (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40541 and fix it if it is affected.

What it is: CVE-2021-40541 is a medium-severity cross-site scripting vulnerability in n/a, published on 11 Oct 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-2021-40541 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-2021-40541/ (Markdown: https://insights.sbomify.com/CVE-2021-40541/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40541
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40541
- OSV: https://osv.dev/vulnerability/CVE-2021-40541

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-40541/
Summaries are generated and may contain mistakes; the official description above is the record.