launch-editor allows users to open files with line numbers in editor from Node.js. Prior to 2.14.2, launch-editor did not escape % on Windows when passing an argument to cmd. When an environment variable contained a malicious value, it was possible that that content to be executed. This vulnerability is fixed in 2.14.2.

Affected: npm: launch-editor, npm: vite, npm: vite-plus

### Summary

`launch-editor` did not escape `%` on Windows when passing an argument to `cmd`. When an environment variable contained a malicious value, it was possible that that content to be executed.

### Impact

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

- The user uses Windows - An attacker can place a file with the malicious filename containing `&` or `%` - Either of - An attacker can inject an environment variable with a malicious value - An attacker can add a NTFS alternate data stream to the file placed

### Details

Unlike `.sh` files, `.bat` / `.cmd` files on Windows cannot be called directly using [`child_process.spawn`](https://nodejs.org/docs/latest-v24.x/api/child_process.html#child_processspawncommand-args-options) and requires passing them as an argument of `cmd.exe`. To do so, launch-editor escapes the arguments passed to `cmd.exe`. But `launch-editor` did not escape `%` which is used for environment variables.

Because `launch-editor` checks if the argument matches an existing filename, the attack requires the attacker to be able to place a file.

- If the attacker can inject an environment variable as well, they can include the subcommand in the env variable (e.g. set ` &calc.exe ` to `%ENV%`) and call `launchEditor` with `something%ENV%`. - If the attacker can place a NTFS alternate data stream to the file (e.g. a NTFS alternate data stream named `~-38%calc.exe`), they can call `launchEditor` with `something %CMDCMDLINE:~-38%c…