Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-14T20:54:56 ua-parser-js: UAParser.js: Denial of Service via crafted Client Hints header 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CWE-1333

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.

A flaw was found in UAParser.js, a JavaScript library for detecting client information. A remote attacker can exploit this vulnerability by sending a specially crafted `Sec-CH-UA-Model` header when the application uses the Client Hints API. This can cause excessive CPU usage due to a regular expression denial-of-service (ReDoS) issue, leading to a denial of service for the affected application.

The `Sec-CH-UA-Model` header is part of the User-Agent Client Hints infrastructure. Mobile browsers send this hint to inform servers about the specific device model. Servers use the model name to tailor content, apply device-specific optimizations, or log analytics about which hardware models access a service. A Regular Expression Denial of Service (ReDoS) vulnerability was found in the ua-parser-js npm package. By sending a crafted `Sec-CH-UA-Model` header to an application that calls `UAParser(headers).withClientHints()`, an attacker can cause the parser to spend excessive CPU time. A single request with a ~32,000-character model value can consume over 400ms of CPU time, with parsing time growing polynomially with input length. The impact is availability only, there is no confidentiality or integrity impact. If you are managing web servers or Node.js applications that process user-agent information, you can defend against this attack vector using the following approaches: * Apply header length restrictions (reverse proxy, WAF, application) * Opt-out of Client Hints, avoid parsing the Sec-CH-UA-Model with ua-parser-js npm package Upgrading to version 2.0.10+ mitigates this issue, by setting a maximum cap size of UA_MAX_LENGTH = 500. Gatekeeper 3 Fix deferred gatekeeper/gatekeeper-rhel9 Migration Toolkit for Containers Fix deferred rhmtc/openshift-migration-ui-rhel8 Red Hat Build of Podman Desktop Fix deferred rh-podman-desktop.git Red Hat Ceph Storage 9 Fix deferred rhceph/alloy-rhel10 Red Hat Enterprise Linux 7 Fix deferred subscription-manager Red Hat Hardened Images Not affected dotnet8.0 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-mlflow-rhel9 Red Hat OpenShift Container Platform 4 Fix deferred openshift4/ose-console Red Hat OpenShift Container Platform 4 Fix deferred openshift4/ose-console-rhel9 https://www.cve.org/CVERecord?id=CVE-2026-48125 https://nvd.nist.gov/vuln/detail/CVE-2026-48125 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