# CVE-2021-24503: Popular Brand SVG Icons - Simple Icons < 2.7.8 - Contributor+ Stored XSS

> Contributors can inject malicious scripts via shortcode parameters, leading to stored XSS when posts are viewed.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 2 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-25qm-8qm2-g8hh

## What is CVE-2021-24503?

CVE-2021-24503 is a medium-severity cross-site scripting vulnerability in Unknown Popular Brand Icons – Simple Icons, published on 2 Aug 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

The Popular Brand Icons – Simple Icons WordPress plugin before 2.7.8 does not sanitise or validate some of its shortcode parameters, such as "color", "size" or "class", allowing users with a role as low as Contributor to set Cross-Site payload in them. A post made by a contributor would still have to be approved by an admin to have the XSS triggered in the frontend, however, higher privilege users, such as editor could exploit this without the need of approval, and even when the blog disallows the unfiltered_html capability.

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

## Which versions are affected by CVE-2021-24503?

It affects 1 product.


Products: Thememason Popular Brand Icons - Simple Icons.

## How do I fix CVE-2021-24503?

No fix has been published for CVE-2021-24503 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-24503 being exploited?

There is no known exploitation of CVE-2021-24503 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-24503 and fix it if it is affected.

What it is: CVE-2021-24503 is a medium-severity cross-site scripting vulnerability in Unknown Popular Brand Icons – Simple Icons, published on 2 Aug 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-24503 in the wild and no public exploit code.

Affected product: Unknown Popular Brand Icons – Simple Icons. 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-2021-24503/ (Markdown: https://insights.sbomify.com/CVE-2021-24503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-24503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-24503
- OSV: https://osv.dev/vulnerability/CVE-2021-24503

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-24503/
Summaries are generated and may contain mistakes; the official description above is the record.