Package Instance

Mermaid does not properly sanitize architecture diagram iconText leading to XSS
### Summary
In the default configuration of mermaid 11.9.0, user supplied input for architecture diagram icons is passed to the d3 `html()` method, creating a sink for cross site scripting.

### Details
Architecture diagram service `iconText` values are passed to the d3 `html()` method, allowing malicious users to inject arbitrary HTML and cause XSS when mermaid-js is used in it's default configuration. 

The vulnerability lies here:

```ts
export const drawServices = async function (
  db: ArchitectureDB,
  elem: D3Element,
  services: ArchitectureService[]
): Promise<number> {
  for (const service of services) {
    /** ... **/
    } else if (service.iconText) {
      bkgElem.html(
        `<g>${await getIconSVG('blank', { height: iconSize, width: iconSize, fallbackPrefix: architectureIcons.prefix })}</g>`
      );
      const textElemContainer = bkgElem.append('g');
      const fo = textElemContainer
        .append('foreignObject')
        .attr('width', iconSize)
        .attr('height', iconSize);
      const divElem = fo
        .append('div')
        .attr('class', 'node-icon-text')
        .attr('style', `height: ${iconSize}px;`)
        .append('div')
        .html(service.iconText); // <- iconText passed into innerHTML
       /** ... **/
};
};
```

This issue was introduced with 734bde38777c9190a5a72e96421c83424442d4e4, around 15 months ago, which was released in [v11.1.0](https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.1.0).

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

```
architecture-beta
    group api(cloud)[API]
    service db "<img src=x onerror=\"document.write(`xss on ${document.domain}`)\">" [Database] in api
```

Here is a PoC on mermaid.live: https://mermaid.live/edit#pako:eNo9T8FOwzAM_ZXI4rBJpWrpRtuIISF24caZZdKyxOsiLUnlJjCo-u9kQ8wX-_n5-dkjKK8ROEhSRxNQhUh4v8cghWMpOvKxZ7I3M3XyUc83L-9v2z9qQPo0CpneMwFPxnZsILU6M--QyNNKCAHaq2jRhfyL0vLZ7jwMiWd3443Q3krjpt38Mv4sgG3WMsi9HHDLjLs4CwcZdGQ08EARM7BISZMgjJdLBIQjWhTAU6nxIOMpCBBuSrJeug_v7b8yPdMdgR_kaUgo9loGXBvZkbS3LqHTSK8-ugC8LMrrEuAjnIEvlnlVL9q6rZu6Lh-rRQbfwKuyyZuybcvqIaWiqKcMfq6uRd7Uy-kXhYFzcA

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

### Remediation
Sanitize the value of `iconText` before passing it to `html()`.

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`.