Inefficient regular expression complexity in UAParser.js - CVE-2026-48125
Published: May 21, 2026
Vulnerability identifier: #VU132091
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-48125
CWE-ID: CWE-1333
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to inefficient regular expression complexity in withClientHints() when parsing a crafted Sec-CH-UA-Model header. A remote attacker can send a specially crafted request to cause a denial of service.
Only server-side applications that call UAParser(headers).withClientHints() are vulnerable.
Affected software
UAParser.js
How to mitigate CVE-2026-48125
Install security update from vendor's website.
UAParser.js - update to 2.0.10