CVE-2026-48125

UAParser.js: Unbounded `Sec-CH-UA-Model` parsing can trigger ReDoS in `withClientHints()`

State: Published
Severity: 5.3 Medium
Published: Jul 14, 2026
Updated: Jul 15, 2026
Reserved: May 20, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	5.3 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L	GitHub_M

Weaknesses

CWE-400 Uncontrolled Resource Consumption
CWE-1333 Inefficient Regular Expression Complexity

Affected Products

Product	Versions
ua-parser-jsfaisalman	>= 2.0.1, < 2.0.10Affected

References

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