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Fencer Vulns
high 7.5

CVE-2021-3803 json

Inefficient Regular Expression Complexity in fb55/nth-check

published 2021-09-17 5 y ago modified 2026-09-10 1 mo ago also GHSA-rp65-9cf3-cjxr , EUVD-2021-2109

cvss
7.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

nth-check is vulnerable to Inefficient Regular Expression Complexity

Patch / fix

  • npm nth-check 2.0.1
  • fb55 fb55/nth-check 2.0.1
  • node-nth-check Debian 14, Debian 13, Debian 12 2.0.1-1

debian advisories DEBIAN-CVE-2021-3803

  • node-nth-check Ubuntu 18.04 LTS 1.0.1-1+deb10u1build0.18.04.1
  • node-nth-check Ubuntu 20.04 LTS 1.0.1-1+deb10u1build0.20.04.1

ubuntu advisories UBUNTU-CVE-2021-3803

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-3803 updated cvss 7.5

nodejs-nth-check: inefficient regular expression complexity

  • Red Hat OpenShift Service Mesh 1 servicemesh-grafana, servicemesh-prometheus, servicemesh-grafana-prometheus
    affected: no fix planned “Out of support scope”
  • Red Hat OpenShift Service Mesh 2.0 servicemesh-grafana, servicemesh-prometheus, servicemesh-grafana-prometheus
    affected: no fix available
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-ui-rhel8, rhacm2/mcm-topology-rhel8, rhacm2/console-header-rhel8
    affected: no fix available “Fix deferred”
  • Red Hat OpenShift Container Platform 4 openshift4/ose-grafana, openshift4/ose-prometheus, openshift4/ose-thanos-rhel8 Red Hat Virtualization 4 ovirt-web-ui, ovirt-engine-ui-extensions
    affected: no fix planned “Will not fix”
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/grc-ui-rhel8, rhacm2/console-rhel8, rhacm2/search-ui-rhel8, rhacm2/application-ui-rhel8, rhacm2/kui-web-terminal-rhel8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.21% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.dev https://huntr.dev/bounties/8cf8cc06-d2cf-4b4e-b42c-99fafb0b04d0 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm nth-check
<2.0.1
2.0.1

Affected products

  • fb55 fb55/nth-check

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.