CVE-2017-16086

HIGH

ua-parser - Regular Expression Denial of Service via UserAgent Header

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2017-16086. PoCs published by Ryan Knell, Sonatype Security Research, Nick Starke, Sonatype Security Research, including Metasploit module auxiliary/dos/http/ua_parser_js_redos.

AI-analyzed exploit summary This Metasploit module exploits a Regular Expression Denial of Service (ReDoS) vulnerability in the 'ua-parser-js' npm module by sending a maliciously crafted User-Agent header to trigger excessive CPU usage, causing service unresponsiveness.

Description

ua-parser is a port of Browserscope's user agent parser. ua-parser is vulnerable to a ReDoS (Regular Expression Denial of Service) attack when given a specially crafted UserAgent header.

Exploits (1)

metasploit WORKING POC
by Ryan Knell, Sonatype Security Research, Nick Starke, Sonatype Security Research · rubypoc
https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/dos/http/ua_parser_js_redos.rb

This Metasploit module exploits a Regular Expression Denial of Service (ReDoS) vulnerability in the 'ua-parser-js' npm module by sending a maliciously crafted User-Agent header to trigger excessive CPU usage, causing service unresponsiveness.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: ua-parser-js npm module versions prior to 0.7.16
No auth needed
Prerequisites: Target service must be using 'ua-parser-js' and expose an HTTP endpoint that processes the User-Agent header
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (1)

Core 1
Core References
Third Party Advisory x_refsource_misc
https://nodesecurity.io/advisories/316

Scores

CVSS v3 7.5
EPSS 0.5777
EPSS Percentile 98.2%
Attack Vector NETWORK
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-400
Status published
Products (2)
npm/ua-parser 0npm
ua-parser_project/ua-parser
Published Jun 07, 2018
Tracked Since Feb 18, 2026