# GHSA-9r27-994c-4xch: discord-html not escaping HTML code blocks when lacking a language identifier

> An attacker can inject malicious HTML into pages using discord-markdown by submitting user-generated markdown without a language identifier.

- **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:** Yes
- **Published:** 24 Feb 2020

## What is GHSA-9r27-994c-4xch?

GHSA-9r27-994c-4xch is a cross-site scripting vulnerability in discord-markdown, published on 24 Feb 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

### Impact
Any website using discord-markdown with user-generated markdown is vulnerable to having code injected into the page where the markdown is displayed.

### Patches
This has been patched in version 2.3.1

### Workarounds
Escape the characters `<>&` before sending plain code blocks to discord-markdown.

### References
https://github.com/brussell98/discord-markdown/issues/13

## Which versions are affected by GHSA-9r27-994c-4xch?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `discord-markdown` | npm | All versions | 2.3.1 |
| `discord-markdown` | npm | All versions | 2.3.1 |

## How do I fix GHSA-9r27-994c-4xch?

Upgrade discord-markdown to 2.3.1 or later.

## Is GHSA-9r27-994c-4xch being exploited?

There is no known exploitation of GHSA-9r27-994c-4xch in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-9r27-994c-4xch and fix it if it is affected.

What it is: GHSA-9r27-994c-4xch is a cross-site scripting vulnerability in discord-markdown, published on 24 Feb 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-9r27-994c-4xch in the wild and no public exploit code.

Affected packages and fixed versions:
- discord-markdown (npm): affected all versions; fixed in 2.3.1
- discord-markdown (npm): affected all versions; fixed in 2.3.1

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-9r27-994c-4xch/ (Markdown: https://insights.sbomify.com/GHSA-9r27-994c-4xch/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-9r27-994c-4xch

---
From sbomify Insights: https://insights.sbomify.com/GHSA-9r27-994c-4xch/
Summaries are generated and may contain mistakes; the official description above is the record.