UAParser.js is a JavaScript library to detect browsers, operating systems, CPUs, and devices from user-agent data. From 2.0.1 until 2.0.10, a regular expression denial-of-service vulnerability exists when using the Client Hints API. By sending a crafted Sec-CH-UA-Model header to an application that calls UAParser(headers).withClientHints(), an attacker can cause excessive CPU time due to catastrophic backtracking in the device regex because Client Hints values are copied without the UA_MAX_LENGTH limit used for User-Agent values. This issue is fixed in version 2.0.10.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 5.3, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and limited availability for affected systems. Impacting 1 product from ua-parser-js_project organizations running these solutions should prioritize assessment and patching.
Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2026-07-14T21:16:57.347
2026-08-06T18:25:08.550
Analyzed
CVSSv3.1: 5.3 (MEDIUM)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | ua-parser-js_project | ua-parser-js | < 2.0.10 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For ua-parser-js_project's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.