# CVE-2021-24563: Frontend Uploader <= 1.3.2 - Unauthenticated Stored Cross-Site Scripting

> Unauthenticated attackers can upload malicious HTML files containing JavaScript, leading to stored cross-site scripting when accessed.

- **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:** 3 Aug 2024
- **Also known as:** GHSA-287r-36rw-cfgc

## What is CVE-2021-24563?

CVE-2021-24563 is a medium-severity cross-site scripting vulnerability in Unknown Frontend Uploader, 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

The Frontend Uploader WordPress plugin through 1.3.2 does not prevent HTML files from being uploaded via its form, allowing unauthenticated user to upload a malicious HTML file containing JavaScript for example, which will be triggered when someone access the file directly

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

## Which versions are affected by CVE-2021-24563?

It affects 1 product.


Products: Frontend Uploader Project Frontend Uploader.

## How do I fix CVE-2021-24563?

No fix has been published for CVE-2021-24563 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-24563 being exploited?

There is no known exploitation of CVE-2021-24563 in the wild and no public exploit code.

Public exploit code:

- The plugin does not prevent HTML files from being uploaded via its form, allowing unauthenticated user to upload a malicious HTML file containing JavaScript for example, which will be triggered when someone access the file directly (github_poc): https://github.com/V35HR4J/CVE-2021-24563
- WordPress Plugin Frontend Uploader 1.3.2 - Stored Cross Site Scripting (XSS) (Unauthenticated) (exploitdb)

## Other vulnerabilities in Unknown Frontend Uploader

- [CVE-2014-9444](https://insights.sbomify.com/CVE-2014-9444/): Cross-site scripting in n/a (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-24563 and fix it if it is affected.

What it is: CVE-2021-24563 is a medium-severity cross-site scripting vulnerability in Unknown Frontend Uploader, 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-2021-24563 in the wild and no public exploit code.

Affected product: Unknown Frontend Uploader. 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-2021-24563/ (Markdown: https://insights.sbomify.com/CVE-2021-24563/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-24563
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-24563
- OSV: https://osv.dev/vulnerability/CVE-2021-24563

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-24563/
Summaries are generated and may contain mistakes; the official description above is the record.