# GHSA-w32g-5hqp-gg6q: Cross-Site Scripting in mermaid

> An attacker can execute arbitrary JavaScript in a victim's browser by providing malicious input to the mermaid diagramming 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:** Yes
- **Published:** 2 Sep 2020

## What is GHSA-w32g-5hqp-gg6q?

GHSA-w32g-5hqp-gg6q is a cross-site scripting vulnerability in mermaid, published on 2 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

Versions of `mermaid` prior to 8.2.3 are vulnerable to Cross-Site Scripting. If malicious input  such as `A["<img src=invalid onerror=alert('XSS')></img>"] ` is provided to the application, it will execute the code instead of rendering it as text due to improper output encoding.

## Recommendation

Upgrade to version 8.2.3 or later

## Which versions are affected by GHSA-w32g-5hqp-gg6q?

2 open source packages ship an affected version, including mermaid.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mermaid` | npm | All versions | 8.2.3 |
| `mermaid` | npm | All versions | 8.2.3 |

## How do I fix GHSA-w32g-5hqp-gg6q?

Upgrade mermaid to 8.2.3 or later.

## Is GHSA-w32g-5hqp-gg6q being exploited?

There is no known exploitation of GHSA-w32g-5hqp-gg6q in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-w32g-5hqp-gg6q and fix it if it is affected.

What it is: GHSA-w32g-5hqp-gg6q is a cross-site scripting vulnerability in mermaid, published on 2 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-w32g-5hqp-gg6q in the wild and no public exploit code.

Affected packages and fixed versions:
- mermaid (npm): affected all versions; fixed in 8.2.3
- mermaid (npm): affected all versions; fixed in 8.2.3

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-w32g-5hqp-gg6q/ (Markdown: https://insights.sbomify.com/GHSA-w32g-5hqp-gg6q/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-w32g-5hqp-gg6q

---
From sbomify Insights: https://insights.sbomify.com/GHSA-w32g-5hqp-gg6q/
Summaries are generated and may contain mistakes; the official description above is the record.