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

> Attackers can cause excessive CPU consumption and service disruption by sending crafted headers to applications using the vulnerable UAParser.js library.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Jul 2026
- **Updated:** 15 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-48125, GHSA-9h5v-pfqq-x599, MINI-jhpp-x6pj-c87x, MINI-v3vr-22m2-6c6h, UBUNTU-CVE-2026-48125

## What is CVE-2026-48125?

CVE-2026-48125 is a medium-severity denial of service vulnerability in faisalman ua-parser-js, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-48125?

2 open source packages ship an affected version, including ua-parser-js. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ua-parser-js` | npm | From 2.0.1 | 2.0.10 |
| `ua-parser-js` | npm | From 2.0.1 | 2.0.10 |

Products: Ua-Parser-Js Project Ua-Parser-Js.

## How do I fix CVE-2026-48125?

Upgrade ua-parser-js to 2.0.10 or later.

## Is CVE-2026-48125 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48125 exists.

## Other vulnerabilities in faisalman ua-parser-js

- [CVE-2021-27292](https://insights.sbomify.com/CVE-2021-27292/): Regular Expression Denial of Service (ReDoS) in ua-parser-js (high 7.5)
- [CVE-2022-25927](https://insights.sbomify.com/CVE-2022-25927/): ReDoS Vulnerability in ua-parser-js version (medium 5.3)
- [CVE-2021-4229](https://insights.sbomify.com/CVE-2021-4229/): ua-parser-js Crypto Mining backdoor (medium 5.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48125 and fix it if it is affected.

What it is: CVE-2026-48125 is a medium-severity denial of service vulnerability in faisalman ua-parser-js, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48125 exists.

Affected packages and fixed versions:
- ua-parser-js (npm): affected from 2.0.1; fixed in 2.0.10
- ua-parser-js (npm): affected from 2.0.1; fixed in 2.0.10

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48125/ (Markdown: https://insights.sbomify.com/CVE-2026-48125/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48125
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48125
- OSV: https://osv.dev/vulnerability/CVE-2026-48125

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48125/
Summaries are generated and may contain mistakes; the official description above is the record.