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Fencer Vulns
medium 5.3

CVE-2021-23364 json

Regular Expression Denial of Service (ReDoS)

published 2021-04-28 5 y ago modified 2026-09-10 1 mo ago also GHSA-w8qv-6jwh-64r5 , EUVD-2021-1216

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

The package browserslist from 4.0.0 and before 4.16.5 are vulnerable to Regular Expression Denial of Service (ReDoS) during parsing of queries.

Patch / fix

  • npm browserslist 4.16.5
  • n/a browserslist 4.16.5
  • node-browserslist Debian 14, Debian 13, Debian 12 4.16.3+~cs5.4.72-2

debian advisories DEBIAN-CVE-2021-23364

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-2021-23364 updated cvss 5.3

browserslist: parsing of invalid queries could result in Regular Expression Denial of Service (ReDoS)

  • 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-rhel8, rhacm2/search-ui-rhel8, rhacm2/console-ui-rhel8, rhacm2/grc-ui-api-rhel8, rhacm2/search-api-rhel8, rhacm2/mcm-topology-rhel8, +3 more
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform 4 openshift4/ose-grafana, openshift4/ose-thanos-rhel9, openshift4/ose-prometheus-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Quay v3 quay/quay-rhel8 v3.6.0-62
    fixed: vendor fix RHSA-2021:3917
  • Red Hat Quay v3 quay/clair-rhel8 v3.6.0-70, quay/quay-builder-rhel8 v3.6.0-44, quay/quay-operator-rhel8 v3.6.0-43, quay/quay-operator-bundle v3.6.0-48, quay/quay-bridge-operator-rhel8 v3.6.0-40, quay/quay-bridge-operator-bundle v3.6.0-35, +3 more Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/grc-ui-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

2.38% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • snyk.io https://snyk.io/vuln/SNYK-JS-BROWSERSLIST-1090194 referenced PoC, tagged "exploit" by a source, unverified
  • snyk.io https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1277182 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm browserslist
>=4.0.0, <4.16.5
4.16.5

Affected products

  • n/a browserslist

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity
  • CWE-400 Uncontrolled Resource Consumption

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.