GHSA-4c7m-wxvm-r7gc
CRITICALGHSA-4c7m-wxvm-r7gc is a critical-severity (CVSS 9.1) CWE-704 vulnerability in netmask. 2 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-4c7m-wxvm-r7gc is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Improper parsing of octal bytes in netmask
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.
netmasknpmDescription
Improper input validation of octal strings in netmask npm package v1.0.6 and below allows unauthenticated remote attackers to perform indeterminate SSRF, RFI, and LFI attacks on many of the dependent packages. A remote unauthenticated attacker can bypass packages relying on netmask to filter IPs and reach critical VPN or LAN hosts.
:exclamation: NOTE: The fix for this issue was incomplete. A subsequent fix was made in version 2.0.1 which was assigned CVE-2021-29418 / GHSA-pch5-whg9-qr2r. For complete protection from this vulnerability an upgrade to version 2.0.1 or later is recommended.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | netmask | all versions | 1.1.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for netmask. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update netmask to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4c7m-wxvm-r7gc is resolved across your whole dependency graph.
Workarounds
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 pinpoints whether GHSA-4c7m-wxvm-r7gc is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-4c7m-wxvm-r7gc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-4c7m-wxvm-r7gc in your dependencies?
O3 detects GHSA-4c7m-wxvm-r7gc across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.