# CVE-2020-7793: ua-parser-js Regular Expression Denial of Service

Source: https://junglewise.ai/threats/cve-2020-7793-ua-parser-js-regular-expression-denial-of-service  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-02-09. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2020-7793 · Severity: low · CVSS 3.1 · Published 2022-02-09

ua-parser-js is a popular JavaScript library used to identify browser, engine, OS, and device details from user-agent strings. A vulnerability in how it processes these strings allows an attacker to send a specially crafted request that causes the system to consume excessive CPU resources. This can lead to a service slowdown or a complete crash, preventing legitimate users from accessing the application.

Technologies: [ua-parser-js (npm)](https://junglewise.ai/threats/technologies/ua-parser-js). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2020-7793 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2020-7793 being exploited in the wild.

**How severe is CVE-2020-7793?** Low severity, with a CVSS score of 3.1, published 9 February 2022.

**Which products and versions are affected?** ua-parser-js (npm) SEMVER:introduced=0,fixed=0.7.23.

**Is there a fix for CVE-2020-7793?** Yes. ua-parser-js (npm): upgrade to 0.7.23 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2020-7793 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2020-7793?** Check whether you run ua-parser-js (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- ua-parser-js (npm): upgrade to 0.7.23 or later

  ```sh
  npm install ua-parser-js@0.7.23
  ```


## Technical details

The ua-parser-js library before version 0.7.23 contains multiple regular expressions susceptible to catastrophic backtracking. An attacker can exploit this by providing a malicious User-Agent string (e.g., containing long sequences of specific characters) that triggers exponential processing time in the regex engine. This is a Regular Expression Denial of Service (ReDoS) vulnerability (CWE-400). The attack can be executed remotely without authentication or user interaction. Successful exploitation results in high CPU exhaustion, leading to a Denial of Service (DoS) condition. The issue is fixed in version 0.7.23 by optimizing the affected regex patterns.

## Affected products

- faisalman ua-parser-js < 0.7.23

## Identifiers

- CVE-2020-7793
- GHSA-394c-5j6w-4xmx

## Timeline

- 2020-10-29: disclosed: Vulnerability disclosed to maintainer
- 2020-12-01: patched: Fix committed to repository
- 2020-12-11: advisory: NVD published CVE-2020-7793

## References

- [https://github.com/faisalman/ua-parser-js/commit/6d1f26df051ba681463ef109d36c9cf0f7e32b18](https://github.com/faisalman/ua-parser-js/commit/6d1f26df051ba681463ef109d36c9cf0f7e32b18)
- [https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf](https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf)
- [https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWERGITHUBFAISALMAN-1050388](https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWERGITHUBFAISALMAN-1050388)
- [https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1050387](https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1050387)
- [https://snyk.io/vuln/SNYK-JS-UAPARSERJS-1023599](https://snyk.io/vuln/SNYK-JS-UAPARSERJS-1023599)

## Related threats

- [faisalman UAParser.js ReDoS in withClientHints](https://junglewise.ai/threats/cve-2026-48125-faisalman-uaparser-js-redos-in-withclienthints)
- [ua-parser-js regular expression denial of service](https://junglewise.ai/threats/cve-2022-25927-ua-parser-js-regular-expression-denial-of-service)
- [ua-parser-js embedded malware in npm package](https://junglewise.ai/threats/cve-2021-4229-ua-parser-js-embedded-malware-in-npm-package)
- [ua-parser-js regular expression denial of service](https://junglewise.ai/threats/cve-2020-7733-ua-parser-js-regular-expression-denial-of-service)
- [ua-parser-js Regular Expression Denial of Service](https://junglewise.ai/threats/cve-2021-27292-ua-parser-js-regular-expression-denial-of-service)