How severe is CVE-2021-27292?

CVE-2021-27292 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-27292?

CVE-2021-27292 affects the following packages: ua-parser-js (npm). Ecosystems affected: npm.

How do I fix CVE-2021-27292?

Update ua-parser-js to 0.7.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27292 is resolved across your whole dependency graph.

How do I detect CVE-2021-27292 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ua-parser-js, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-27292 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2021-27292 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-27292, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-27292?

CVE-2021-27292 has an EPSS (Exploit Prediction Scoring System) score of 3.4%, placing it in the 89th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2021-27292 published, and has it been updated?

CVE-2021-27292 was published on March 17, 2021 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2021-27292 — ua-parser-js

HIGHFix: faisalman/ua-parser-js@809439e

CVE-2021-27292 is a high-severity (CVSS 7.5) vulnerability in ua-parser-js. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for ua-parser-js — see the affected versions and patch details below.

Regular Expression Denial of Service (ReDoS) in ua-parser-js

Also known asGHSA-78cj-fxph-m83p

Published

Mar 17, 2021

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs89th percentile — riskier than 89% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

3Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

ua-parser-jsnpm

46.4Mdownloads / week

Description

ua-parser-js >= 0.7.14, fixed in 0.7.24, uses a regular expression which is vulnerable to denial of service. If an attacker sends a malicious User-Agent header, ua-parser-js will get stuck processing it for an extended period of time.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`ua-parser-js`	≥ 0.7.14&&< 0.7.24	0.7.24`npm install ua-parser-js@0.7.24`

Affected Products

1 product · 1 configurations

Application

ua-parser-jsua-parser-js_project

≥ 0.7.14 && < 0.7.24

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

ua-parser-js >= 0.7.14, fixed in 0.7.24, uses a regular expression which…

gist.github.comNVDMar 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ua-parser-js, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ua-parser-js to 0.7.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27292 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

While some components do package a vulnerable version of ua-parser-js, access to them requires OpenShift OAuth credentials and hence have been marked with a Low impact. This applies to the following products: - OpenShift Container Platform (OCP) - OpenShift ServiceMesh (OSSM) - Red Hat OpenShift Jaeger (RHOSJ) - Red…

Product	Fixed in	Advisory
OpenShift Logging 5.1	`openshift-logging/kibana6-rhel8:v6.8.1-108`	RHSA-2022:0226
OpenShift Logging 5.2	`openshift-logging/kibana6-rhel8:v6.8.1-110`	RHSA-2022:0230
OpenShift Logging 5.3	`openshift-logging/kibana6-rhel8:v6.8.1-109`	RHSA-2022:0227
Red Hat OpenShift Container Platform 4.8	`openshift4/ose-console:v4.8.0-202107010336.p0.git.188a490.assembly.stream`	RHSA-2021:2438
Red Hat OpenShift Jaeger 1.24	`distributed-tracing/jaeger-agent-rhel8:1.24.0-9`	RHSA-2021:3024

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-27292 in your dependencies?

Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

7.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

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

Weaponization

No Nuclei template or Metasploit module yet. 1 public proof-of-concept reference is listed on this page.

OpenSSF Scorecard

Package health score

ua-parser-js

7.5/10

Maintained7/10

Code-Review1/10

Vulnerabilities0/10

Branch-Protection4/10

Dependency-Update-Tool10/10

Assessed Oct 30, 2026

Timeline

Disclosed

Mar 17, 2021

First exploit

Mar 23, 2021

6 days after disclosure — rapid exploitation

Last updated

Oct 20, 2026

Identifiers

CVE-2021-27292

GHSA-78cj-fxph-m83p

References

Advisorynvd.nist.gov · CVE 2021 27292 Fixgithub.com · 809439e20e273ce0d25c1d04e111dcf6011eb566 Fixgithub.com · 2e7e8c4a7b318f4032493773732754e418279a14 Evidencegist.github.com · 6941d80d6b4e694df4bc269493b7be76

Related vulnerabilities

This CVE is high severity; 4 of 5 other CVEs affecting ua-parser-js are rated as high or higher (top: high).

CVE-2026-48125CVE-2022-25927CVE-2020-7793CVE-2021-4229CVE-2020-7733

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026

CVE-2021-27292 — ua-parser-js

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2021-27292 in your dependencies?