NVD / CVE Program· CNA GitHub_M

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

MediumCVSS 5.3 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 21/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.52% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: faisalman ua-parser-js 2.0.10.

Low priority for now. Upgrade to faisalman ua-parser-js 2.0.10 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

GHSA-9h5v-pfqq-x599

Published: Jul 14, 2026
Updated: Oct 24, 2026
EPSS: 0.5% · 44th percentile
CWE: CWE-400

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 21 / 40 · 5.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.5%

CISA SSVC decision

Exploitation: proof of concept
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 5.3; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is the ua-parser-js on your site affected?Scan JavaScript libraries

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
ua-parser-js project	ua-parser-js	cpe:2.3:a:ua-parser-js_project:ua-parser-js

Is the ua-parser-js on your site affected?

The free JavaScript library scanner reads the ua-parser-js version from the files your site loads, matches this record and other known vulnerabilities, and gives the safe version on the same branch. If the version can't be read, it says so. No account needed.

Scan JavaScript libraries

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

ua-parser-js project ua-parser-js2.0.1 and later · before 2.0.10

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

faisalman ua-parser-js
- >= 2.0.1, < 2.0.10affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	node-ua-parser-js	from 0	—
Debian:14	node-ua-parser-js	before 2.0.10+ds+~cs0.3.5-1	2.0.10+ds+~cs0.3.5-1
npm	ua-parser-js	from 2.0.1 · before 2.0.10	2.0.10

Same product

ua-parser-js project: all records

Other highest-scoring records for the same primary product.

CVE-2021-4229ua-parser-js Crypto Mining backdoor
35Monitor
CVE-2022-25927Versions of the package ua-parser-js from 0.7.30 and before 0.7.33, from 0.8.1 and before 1.0.33 are vulnerable to Regular Expression…
31Monitor
CVE-2021-27292ua-parser-js >= 0.7.14, fixed in 0.7.24, uses a regular expression which is vulnerable to denial of service.
31Monitor

Published before and after this one in the same product

← EarlierCVE-2020-7733Sep 16, 2020 · Regular Expression Denial of Service (ReDoS)
31Monitor
← EarlierCVE-2020-7793Dec 11, 2020 · Regular Expression Denial of Service (ReDoS)
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
faisalman ua-parser-js	2.0.10 · description	Vendor (CNA)
debian:node-ua-parser-js	2.0.10+ds+~cs0.3.5-1 · Debian:14	Package registry (OSV)
npm:ua-parser-js	2.0.10	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

faisalman/ua-parser-jscommit 90354d3

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: low · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: Low

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

nvd-secondary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}