Improper regular expression in Vue's parseHTML function leads to a potential regular expression denial of service vulnerability.

Affected: npm: vue

The ReDoS can be exploited through the `parseHTML` function in the `html-parser.ts` file. This flaw allows attackers to slow down the application by providing specially crafted input that causes inefficient processing of regular expressions, leading to excessive resource consumption.

To demonstrate this vulnerability, here's an example. In a Vue client-side application, create a new Vue instance with a template string that includes a `<script>` tag but closes it incorrectly with something like `</textarea>`.

```javascript new Vue({ el: '#app', template: ' <div> Hello, world! <script>${'<'.repeat(1000000)}</textarea> </div>' }); ``` Next, set up a basic HTML page (e.g., index.html) to load this JavaScript and mount the Vue instance:

```html <!DOCTYPE html> <html> <head> <title>My first Vue app</title> </head> <body> <div id=\"app\">Loading...</div> </body> </html> ```

When you visit the app in your browser at http://localhost:3000, you'll notice that the time taken to parse and mount the Vue application increases significantly due to the ReDoS vulnerability, demonstrating how the flaw can affect performance.