Package Instance

Mermaid improperly sanitizes sequence diagram labels leading to XSS
### Summary
In the default configuration of mermaid 11.9.0, user supplied input for sequence diagram labels is passed to `innerHTML` during calculation of element size, causing XSS.

### Details
Sequence diagram node labels with KaTeX delimiters are passed through `calculateMathMLDimensions`. This method passes the full label to `innerHTML` which allows allows malicious users to inject arbitrary HTML and cause XSS when mermaid-js is used in it's default configuration (with KaTeX support enabled). 

The vulnerability lies here:

```ts
export const calculateMathMLDimensions = async (text: string, config: MermaidConfig) => {
  text = await renderKatex(text, config);
  const divElem = document.createElement('div');
  divElem.innerHTML = text; // XSS sink, text has not been sanitized.
  divElem.id = 'katex-temp';
  divElem.style.visibility = 'hidden';
  divElem.style.position = 'absolute';
  divElem.style.top = '0';
  const body = document.querySelector('body');
  body?.insertAdjacentElement('beforeend', divElem);
  const dim = { width: divElem.clientWidth, height: divElem.clientHeight };
  divElem.remove();
  return dim;
};
```

The `calculateMathMLDimensions` method was introduced in 5c69e5fdb004a6d0a2abe97e23d26e223a059832 two years ago, which was released in [Mermaid 10.9.0](https://github.com/mermaid-js/mermaid/releases/tag/v10.9.0).

### PoC
Render the following diagram and observe the modified DOM.

```
sequenceDiagram
    participant A as Alice<img src="x" onerror="document.write(`xss on ${document.domain}`)">$$\\text{Alice}$$
    A->>John: Hello John, how are you?
    Alice-)John: See you later!
```

Here is a PoC on mermaid.live: https://mermaid.live/edit#pako:eNpVUMtOwzAQ_BWzyoFKaRTyaFILiio4IK7ckA-1km1iKbaLY6spUf4dJ0AF68uOZ2dm7REqXSNQ6PHDoarwWfDGcMkUudaJGysqceLKkj3hPdl3osJ7IRvSm-qBwcCAaIXGaONRrSsnUdnobITF28PQ954lwXglai25UNNhxWAXBMyXxcGOi-3kL_5k79e73atuFSUv2HWazH1IWn0m3CC5aPf4b3p2WK--BW-4DJCOWzQ3TM0HQmiMqIFa4zAEicZv4iGMsw0D26JEBtS3NR656ywDpiYv869_11r-Ko12TQv0yLveI3eqfcjP111HUNVonrRTFuhdsVgAHWEAmuRxlG7SuEzKMi-yJAnhAjTLIk_EcbFJtuk2y9MphM8lM47KIp--AOZghtU

### Impact
XSS on all sites that use mermaid and render user supplied diagrams without further sanitization.

### Remediation
The value of the `text` argument for the `calculateMathMLDimensions` method needs to be sanitized before getting passed on to `innerHTML`.

Prototype pollution vulnerability found in Mermaid's bundled version of DOMPurify
The following bundled files within the Mermaid NPM package contain a bundled version of DOMPurify that is vulnerable to https://github.com/cure53/DOMPurify/security/advisories/GHSA-mmhx-hmjr-r674, potentially resulting in an XSS attack.

This affects the built:

- `dist/mermaid.min.js`
- `dist/mermaid.js`
- `dist/mermaid.esm.mjs`
- `dist/mermaid.esm.min.mjs`

This will also affect users that use the above files via a CDN link, e.g. `https://cdn.jsdelivr.net/npm/mermaid@10.9.2/dist/mermaid.min.js`

**Users that use the default NPM export of `mermaid`, e.g. `import mermaid from 'mermaid'`, or the `dist/mermaid.core.mjs` file, do not use this bundled version of DOMPurify, and can easily update using their package manager with something like `npm audit fix`.**

### Patches

- `develop` branch: 6c785c93166c151d27d328ddf68a13d9d65adc00
- backport to v10: 92a07ffe40aab2769dd1c3431b4eb5beac282b34