# CVE-2023-3521: Cross-site Scripting (XSS) - Reflected in fossbilling/fossbilling

> Reflected Cross-Site Scripting in FOSSBilling allows attackers to execute arbitrary scripts in victim browsers, potentially leading to session hijacking or data theft.

- **Severity:** Medium 5.4 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/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:** 6 Jul 2023
- **Updated:** 31 Oct 2024
- **Also known as:** GHSA-f2hf-p7mp-7x9v

## What is CVE-2023-3521?

CVE-2023-3521 is a medium-severity cross-site scripting vulnerability in fossbilling/fossbilling, published on 6 Jul 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

Cross-site Scripting (XSS) - Reflected in GitHub repository fossbilling/fossbilling prior to 0.5.4.

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

## Which versions are affected by CVE-2023-3521?

It affects 1 product.


Products: Fossbilling Fossbilling.

## How do I fix CVE-2023-3521?

No fix has been published for CVE-2023-3521 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-3521 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-3521 exists.

Public exploit code:

- FOSSBilling < 0.5.3 - Cross-Site Scripting (nuclei): http/cves/2023/CVE-2023-3521.yaml

## Other vulnerabilities in fossbilling/fossbilling

- [CVE-2023-3490](https://insights.sbomify.com/CVE-2023-3490/): SQL Injection in fossbilling/fossbilling (critical 9.8)
- [CVE-2023-3491](https://insights.sbomify.com/CVE-2023-3491/): Unrestricted Upload of File with Dangerous Type in fossbilling/fossbilling (high 8.0)
- [CVE-2023-3393](https://insights.sbomify.com/CVE-2023-3393/): Code Injection in fossbilling/fossbilling (high 8.0)
- [CVE-2023-3493](https://insights.sbomify.com/CVE-2023-3493/): Improper Neutralization of Formula Elements in a CSV File in fossbilling/fossbilling (high 7.7)
- [CVE-2023-3394](https://insights.sbomify.com/CVE-2023-3394/): Session Fixation in fossbilling/fossbilling (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-3521 and fix it if it is affected.

What it is: CVE-2023-3521 is a medium-severity cross-site scripting vulnerability in fossbilling/fossbilling, published on 6 Jul 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-3521 exists.

Affected product: fossbilling/fossbilling. 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-2023-3521/ (Markdown: https://insights.sbomify.com/CVE-2023-3521/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-3521
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-3521
- OSV: https://osv.dev/vulnerability/CVE-2023-3521

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-3521/
Summaries are generated and may contain mistakes; the official description above is the record.