Medium severity · published Jul 14, 2026
CVE-2026-48125
UAParser.js: Unbounded `Sec-CH-UA-Model` parsing can trigger ReDoS in `withClientHints()`
5.3
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 44% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
UA
ua-parser-js · faisalman
>= 2.0.1, < 2.0.10 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-48125
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-48125
Patch
https://github.com/faisalman/ua-parser-js/commit/90354d3458495628b1d3ba68a9d76673e6d14fc5
Release Notes
https://github.com/faisalman/ua-parser-js/releases/tag/2.0.10
Exploit
https://github.com/faisalman/ua-parser-js/security/advisories/GHSA-9h5v-pfqq-x599