launch-editor: Editor CLI flag misinterpretation causing arbitrary command execution for some editors

Summary

launch-editor forwarded file paths directly to editors without sanitization. If a path resembles a CLI flag, editors like Vim may interpret it as a command, potentially causing unintended file overwrites or command execution.

Impact

Direct launch-editor users

Only apps that match all of the following conditions are affected:

• The attacker is able to create a file system entry (e.g. a file or directory) starting with + or - in the working directory
• The user uses or the app specifies any of the following editors:
• Vim (including gVim)
• MacVim
• Emacs (including Emacsclient)
• Notepad++ (only if using a plugin exposing dangerous operations via plugin messages)
• The first argument of launchEditor can start with + or - or the user is using WSL

launch-editor-middleware users

Only apps that match the following conditions are affected:

• The attacker is able to create a file system entry (e.g. a file or directory) starting with + or - in the working directory
• The user uses or the app specifies any of the following editors:
• Vim (including gVim)
• MacVim
• Emacs (including Emacsclient)
• Notepad++ (only if using a plugin exposing dangerous operations via plugin messages)
• launch-editor older than v2.2.0 is used, or the user is using WSL

Vite users

Only apps that match the following conditions are affected:

• The attacker is able to create a file system entry (e.g. a file or directory) starting with + or - in the working directory
• The user uses or the app specifies any of the following editors:
• Vim (including gVim)
• MacVim
• Emacs (including Emacsclient)
• Notepad++ (only if using a plugin exposing dangerous operations via plugin messages)
• The user is using WSL

Details

launchEditor(file) function passes the file name as-is to the editor if the file with that file name exists. If the file name starts with - (also + for Vim), the editor treats them as flags rather than positional arguments. For example, Vim treats arguments starting with + as an Ex command. As a result, an existing relative directory such as:

+call writefile(["SAFE_MARKER"],"LAUNCH_EDITOR_MARKER")|qa!

is not treated as a filename when passed to Vim. Vim executes the embedded Ex command.

The following editor has a potentially destructive operation exposed to the CLI arguments:

• Vim (including gVim)
• MacVim
• Emacs (including Emacsclient)
• Notepad++ (only if using a plugin exposing dangerous operations via plugin messages)

launch-editor-middleware v2.2.0+ converts the passed file path to an absolute path so those are not affected as long as the user is not using WSL. For WSL, launch-editor converts the paths to relative paths internally, so those are still affected.

Vite 2.0.0+ uses launch-editor-middleware v2.2.0+ so the WSL users are only affected.