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Fencer Intel
medium 5.9

CVE-2026-4923 json

path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards

published 7mo ago modified 2mo ago also EUVD-2026-16322 , GHSA-27v5-c462-wpq7

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

Impact:

When using multiple wildcards, combined with at least one parameter, a regular expression can be generated that is vulnerable to ReDoS. This backtracking vulnerability requires the second wildcard to be somewhere other than the end of the path.

Unsafe examples:

/*foo-*bar-:baz /*a-:b-*c-:d /x/*a-:b/*c/y

Safe examples:

/*foo-:bar /*foo-:bar-*baz

Patches:

Upgrade to version 8.4.0.

Workarounds:

If you are using multiple wildcard parameters, you can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable.

Patch / fix

  • npm path-to-regexp 8.4.0
  • path-to-regexp path-to-regexp 8.4.0
  • node-path-to-regexp Debian 14 8.4.0-1

debian advisories DEBIAN-CVE-2026-4923

Is CVE-2026-4923 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2026-4923 updated cvss 5.9

path-to-regexp: path-to-regexp: Denial of Service via specially crafted paths with multiple wildcards

  • Red Hat Cryostat 4 io.cryostat-cryostat, cryostat/cryostat-openshift-console-plugin-rhel9 Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/kibana6-rhel8, openshift-logging/elasticsearch6-rhel9, openshift-logging/logging-curator5-rhel9, openshift-logging/elasticsearch-proxy-rhel9, openshift-logging/elasticsearch-rhel9-operator, openshift-logging/elasticsearch-operator-bundle Red Hat Migration Toolkit for Applications 8 mta/mta-ui-rhel9 Red Hat Migration Toolkit for Virtualization mtv-candidate/mtv-console-plugin-rhel9, migration-toolkit-virtualization/mtv-console-plugin-rhel9 Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat Network Observability Operator network-observability/network-observability-console-plugin-rhel9
    +34 more products
    Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-console-plugin-rhel9, openshift-lightspeed/lightspeed-console-plugin-pf5-rhel9 Red Hat OpenShift Pipelines openshift-pipelines/pipelines-console-plugin-rhel8, openshift-pipelines/pipelines-console-plugin-rhel9 Red Hat OpenShift Service Mesh 2 openshift-service-mesh/kiali-rhel8, openshift-service-mesh/kiali-ossmc-rhel8 Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9, openshift-service-mesh/kiali-ossmc-rhel9, openshift-service-mesh/kiali-rhel9-operator, openshift-service-mesh/kiali-operator-bundle Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8 Red Hat AMQ Broker 7 org.jolokia-jolokia-parent, amq7-tech-preview/amq-broker-jolokia-api-server-rhel9 Red Hat Ansible Automation Platform 2 automation-gateway, automation-controller, automation-platform-ui, automation-eda-controller, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-tech-preview/mcp-server-rhel9 Red Hat build of Apache Camel - HawtIO 4 io.hawt-project Red Hat build of Apicurio Registry 2 io.apicurio-apicurio-registry Red Hat Build of Podman Desktop podman-desktop-macos-1-0, podman-desktop-windows-1-0 Red Hat Data Grid 8 org.infinispan-infinispan-console Red Hat Developer Hub 1 rhdh/backstage-community-plugin-catalog-backend-module-scaffolder-relation-processor Red Hat Edge Manager 1 rhem/flightctl-ui-rhel9, rhem/flightctl-ui-ocp-rhel9 Red Hat Enterprise Linux 8 pcs, mozjs60, pcs-snmp Red Hat Enterprise Linux 9 gjs, pcs, sgx-mpa, tdx-qgs, pcs-snmp, sgx-libs, +5 more Red Hat Enterprise Linux 10 linux-sgx Red Hat Fuse 7 io.hawt-project, io.apicurio-apicurito, io.hawt-hawtio-online, io.syndesis-syndesis-parent Red Hat JBoss Enterprise Application Platform 7 io.hawt-project Red Hat JBoss Enterprise Application Platform 8 io.hawt-project Red Hat JBoss Enterprise Application Platform Expansion Pack io.hawt-project, org.keycloak-keycloak-parent Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-data-science-pipelines-argo-argoexec-rhel8, rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9, rhoai/odh-data-science-pipelines-argo-workflowcontroller-rhel8 Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-monitoring-plugin-rhel9, openshift4/ose-agent-installer-ui-rhel9 Red Hat Openshift Data Foundation 4 odf4/mcg-core-rhel9, odf4/odf-console-rhel9, odf4/ocs-client-console-rhel9, odf4/odf-multicluster-console-rhel9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/jetbrains-ide-rhel9 Red Hat OpenShift distributed tracing 3 rhosdt/tempo-jaeger-query-rhel9 Red Hat OpenShift GitOps openshift-gitops-1/argocd-rhel8, openshift-gitops-1/argocd-rhel9, openshift-gitops-1/console-plugin-rhel8 Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-console-plugin, container-native-virtualization/kubevirt-console-plugin-rhel9 Red Hat Process Automation 7 org.uberfire-uberfire-parent, org.kie-process-migration-service Red Hat Quay 3 quay/quay-rhel8 Red Hat Satellite 6 nodejs-react-router, nodejs-react-router-dom Red Hat Single Sign-On 7 org.keycloak-keycloak-parent Red Hat Trusted Artifact Signer rhtas/rhtas-console-ui-rhel9 Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    affected: workaround, no fix available “Fix deferred”

1 more affected, 1 more fixed, 1 more not affected in the full advisory

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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
7mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm path-to-regexp
>=8.0.0, <8.4.0
8.4.0

Affected products

  • path-to-regexp path-to-regexp

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Intel 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.

The maintainers of pillarjs/path-to-regexp published their own advisory on GitHub. Reviewed sources take precedence over it.