This appears to require attacker controlled data already being written to a settings XML file in specific locations on disk.
Put simply, this requires another prerequisite arbitrary file write vulnerability to be reachable.
This isn’t “zero click” unless we’re going under the assumption that an attacker already has full control over my machine before that. At best, this is a persistence mechanism, not initial access.
Steps to reproduce:
1. Place a malicious file on disk (e.g. ~/Downloads/definitely_legit.exe)
2. Modify shortcuts.xml (in the user's %AppData%, requiring local user permissions) to point to this file in a special way
3. The shortcut triggers and runs the exe when the user next starts and uses Notepad++ (the user needs to trigger the shortcut, but that can be something that they will do anyway such as typing any key)
This functionality is by design, but by prefixing a trusted path and then /../'ing your way back out of the trusted location, it doesn't show a warning before executing
Vulnerability rated as high because of the impact, despite the near-impossible exploitability. The CVSS vector for "email the user a malicious file and have them save and execute it", not bothering with the whole shortcuts method, would result in an even higher rating...
don't you mean "x and y" instead of "either x or y"?
It's not triggered by a default-configured shortcut, you need both modifying of the shortcuts definition file and the target user to trigger it. Notably, modifying the shortcuts definition file requires a permission level equal to or higher than the user has
If an attacker can already either modify the existing shortcuts.xml file or convince me to download and run a .lnk file that links to a different one they managed to get onto my computer then they don't need to use Notepad++ to do their dirty work.
To me it feels like people who build LEGO their whole lives but never once stray away from the step-by-step manual and never have built something "outside the box".