CVE-2021-27191 is a high-severity (CVSS 7.5) vulnerability in get-ip-range. 1 public exploit reference exists, so weaponization risk is real. A fix is available for get-ip-range — see the affected versions and patch details below.
Denial of Service in get-ip-range
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-27191 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
get-ip-rangenpmDescription
The get-ip-range package before 4.0.0 for Node.js is vulnerable to denial of service (DoS) if the range is untrusted input. An attacker could send a large range (such as 128.0.0.0/1) that causes resource exhaustion. Update get-ip-range dependency to 4.0.0 or above.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | get-ip-range | all versions | 4.0.0npm install get-ip-range@4.0.0 |
Affected Products
get-ip-rangeget-ip-range_projectResearch 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 get-ip-range, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update get-ip-range to 4.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27191 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2021-27191 in your dependencies?
Find it across npm, including transitive dependencies.