# GHSA-pxmp-fwjc-4x7q: HTML Injection in marky-markdown

> Attacker can inject malicious HTML via bypassed iframe validation, leading to potential code execution in user browsers.

- **Severity:** Not scored
- **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:** 3 Sep 2020

## What is GHSA-pxmp-fwjc-4x7q?

GHSA-pxmp-fwjc-4x7q is a cross-site scripting vulnerability in marky-markdown, published on 3 Sep 2020. 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

All versions of `marky-markdown` are vulnerable to HTML Injection due to a validation bypass. The package only allows iframes where the source is `youtube.com` but it is possible to bypass the validation with sources where `youtube.com` is the sub-domain, such as `youtube.com.evil.co`. This 

## Recommendation

This package is no longer maintained. Please upgrade to `@npmcorp/marky-markdown`

## Which versions are affected by GHSA-pxmp-fwjc-4x7q?

2 open source packages ship an affected version, including marky-markdown.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `marky-markdown` | npm | From 0.0.0 | None |
| `marky-markdown` | npm | From 0.0.0 | None |

## How do I fix GHSA-pxmp-fwjc-4x7q?

No fix has been published for GHSA-pxmp-fwjc-4x7q yet. Limit exposure of the affected software until one is available.

## Is GHSA-pxmp-fwjc-4x7q being exploited?

There is no known exploitation of GHSA-pxmp-fwjc-4x7q in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-pxmp-fwjc-4x7q and fix it if it is affected.

What it is: GHSA-pxmp-fwjc-4x7q is a cross-site scripting vulnerability in marky-markdown, published on 3 Sep 2020. 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 GHSA-pxmp-fwjc-4x7q in the wild and no public exploit code.

Affected packages and fixed versions:
- marky-markdown (npm): affected from 0.0.0; no fix listed
- marky-markdown (npm): affected from 0.0.0; no fix listed

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/GHSA-pxmp-fwjc-4x7q/ (Markdown: https://insights.sbomify.com/GHSA-pxmp-fwjc-4x7q/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-pxmp-fwjc-4x7q

---
From sbomify Insights: https://insights.sbomify.com/GHSA-pxmp-fwjc-4x7q/
Summaries are generated and may contain mistakes; the official description above is the record.