What’s Vulnerable › Vulnerabilities

CVE-2026-48125: UAParser.js: Unbounded `Sec-CH-UA-Model` parsing can trigger ReDoS in `withClientHints()`

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-14 · updated 2026-10-24
• Weakness: CWE-400

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.

Affected products

• ua-parser-js: from 2.0.1 before 2.0.10 — fixed in 2.0.10

How to fix

Upgrade to a fixed version: ua-parser-js 2.0.10. Check the vendor advisory for mitigations.

References

• https://github.com/faisalman/ua-parser-js/commit/90354d3458495628b1d3ba68a9d76673e6d14fc5
• https://github.com/faisalman/ua-parser-js/releases/tag/2.0.10
• https://github.com/faisalman/ua-parser-js/security/advisories/GHSA-9h5v-pfqq-x599
• https://github.com/faisalman/ua-parser-js/security/advisories/GHSA-9h5v-pfqq-x599

Get alerted when CVE-2026-48125 or the next vulnerability affects your stack