Clipboard-based DOM-XSS
ImpactA self Cross-Site Scripting vulnerability exists in the @github/paste-markdown library. If the clipboard data contains the string `<table>`, a **div** is dynamically created, and the clipboard content is copied into its **innerHTML** property without any sanitization, resulting in improper execution of JavaScript in the browser of the victim (the user who pasted the code). Users directed to copy text from a malicious website and paste it into pages that utilize this library are affected.The following @github/paste-markdown code snippet is triggered when the user pastes something and the browser's clipboard data contains an entry whose content-type is **text/HTML**.PatchesA security patch was released in [version 0.3.4](https://github.com/github/paste-markdown/releases/tag/v0.3.4).WorkaroundsA Content Security Policy that prevents `unsafe-inline` helps reduce the likelihood of this vulnerability being exploited in modern browsers.