# GHSA-5ff8-jcf9-fw62: Cross-Site Scripting in markdown-it-katex

> Attackers can execute arbitrary JavaScript in victims' browsers via unescaped error messages in the markdown-it-katex library.

- **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:** 4 Sep 2020

## What is GHSA-5ff8-jcf9-fw62?

GHSA-5ff8-jcf9-fw62 is a cross-site scripting vulnerability in markdown-it-katex, published on 4 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 `markdown-it-katex` are vulnerable to Cross-Site Scripting (XSS). The package fails to properly escape error messages, which may allow attackers to execute arbitrary JavaScript in a victim's browser by triggering an error.

## Recommendation

No fix is currently available. Consider using an alternative package until a fix is made available.

## Which versions are affected by GHSA-5ff8-jcf9-fw62?

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


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

## How do I fix GHSA-5ff8-jcf9-fw62?

No fix has been published for GHSA-5ff8-jcf9-fw62 yet. Limit exposure of the affected software until one is available.

## Is GHSA-5ff8-jcf9-fw62 being exploited?

There is no known exploitation of GHSA-5ff8-jcf9-fw62 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-5ff8-jcf9-fw62 and fix it if it is affected.

What it is: GHSA-5ff8-jcf9-fw62 is a cross-site scripting vulnerability in markdown-it-katex, published on 4 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-5ff8-jcf9-fw62 in the wild and no public exploit code.

Affected packages and fixed versions:
- markdown-it-katex (npm): affected from 0.0.0; no fix listed
- markdown-it-katex (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-5ff8-jcf9-fw62/ (Markdown: https://insights.sbomify.com/GHSA-5ff8-jcf9-fw62/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-5ff8-jcf9-fw62

---
From sbomify Insights: https://insights.sbomify.com/GHSA-5ff8-jcf9-fw62/
Summaries are generated and may contain mistakes; the official description above is the record.