Joplin is a free, open source note taking and to-do application. A Cross-site Scripting (XSS) vulnerability allows pasting untrusted data into the rich text editor to execute arbitrary code. HTML pasted into the rich text editor is not sanitized (or not sanitized properly). As such, the `onload` attribute of pasted images can execute arbitrary code. Because the TinyMCE editor frame does not use the `sandbox` attribute, such scripts can access NodeJS's `require` through the `top` variable. From this, an attacker can run arbitrary commands. This issue has been addressed in version 2.12.10 and users are advised to upgrade. There are no known workarounds for this vulnerability.