UAParser.js: Unbounded `Sec-CH-UA-Model` parsing can trigger ReDoS in `withClientHints()`
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Partial Red Hat: 7 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-1333.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| faisalman | ua-parser-js | 2.0.1 to before 2.0.10 | 2.0.10 | Patch available | CNA |
| — | ua-parser-js (npm) | 2.0.1 to before 2.0.10 | 2.0.10 | Patch available | GHSA-9h5v-pfqq-x599 |
- ua-parser-js Vendorfaisalman Affected 2.0.1 to before 2.0.10 Fixed in 2.0.10 Patch available CNA
- ua-parser-js (npm) Vendor— Affected 2.0.1 to before 2.0.10 Fixed in 2.0.10 Patch available GHSA-9h5v-pfqq-x599
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:ua-parser-js_project:ua-parser-js:*:*:*:*:*:node.js:*:* | 2.0.1 to before 2.0.10 | Vulnerable | Ua-parser-js Project |
- cpe:2.3:a:ua-parser-js_project:ua-parser-js:*:*:*:*:*:node.js:*:* Versions 2.0.1 to before 2.0.10 Vulnerable ·Ua-parser-js Project
Remediation
- Fix · CNA ua-parser-js (faisalman) Fixed in 2.0.10
- Fix · GHSA-9h5v-pfqq-x599 ua-parser-js (npm) Fixed in 2.0.10 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Gatekeeper 3 | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Containers | Affected | No fix yet: Fix deferred |
| Red Hat Build of Podman Desktop | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Hardened Images
- Red Hat OpenShift AI (RHOAI)
Timeline
- 2026-10-02 Threatist record created from CVE-2026-48125
- 2026-10-03 Alias added: GHSA-9h5v-pfqq-x599
- 2026-11-06 Affected versions changed · Red Hat
References
More Ua-parser-js Project Ua-parser-js vulnerabilities
- TI-2022-09474 Regular expression denial of service in ua-parser-js CVSS 3.1HIGH 7.5
- TI-2021-03090 ua-parser-js Crypto Mining backdoor CVSS 3.1HIGH 8.8
- TI-2020-06309 Regular expression denial of service (ReDoS) in ua-parser-js CVSS 3.1HIGH 7.5
- TI-2020-06251 Regular expression denial of service (ReDoS) in ua-parser-js CVSS 3.1HIGH 7.5
- TI-2021-08826 ua-parser-js >= 0.7.14, fixed in 0.7.24, uses a regular expression which is vulnerable to… CVSS 3.1HIGH 7.5
Sources
- CVE-2026-48125 · CVE Program
- CVE-2026-48125 · NVD
- FIRST EPSS
- GHSA-9h5v-pfqq-x599 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-48125 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences