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Fencer Intel
high 7.5

CVE-2026-59887 json

linkify-it: Quadratic-complexity DoS via the `mailto:` validator scan-loop on attacker text

published 4mo ago modified 17d ago also EUVD-2026-42321 , GHSA-v245-v573-v5vm

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

linkify-it is a links recognition library with full Unicode support. Prior to 5.0.2, the mailto: schema validator used by .test() and .match() can be invoked at every mailto: occurrence and scan the remaining input through src_email_name in lib/re.mjs, causing O(n^2) CPU consumption on crafted user text. This issue is fixed in version 5.0.2.

Patch / fix

  • npm linkify-it 5.0.2
  • markdown-it linkify-it 5.0.2

Is CVE-2026-59887 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-2026-59887 updated cvss 7.5

linkify-it: linkify-it: Denial of Service via crafted mailto: links

  • Red Hat Node HealthCheck Operator workload-availability/node-remediation-console-rhel8, workload-availability/node-remediation-console-rhel9, workload-availability/node-healthcheck-rhel9-operator, workload-availability/node-healthcheck-operator-bundle, workload-availability/node-healthcheck-must-gather-rhel9 Red Hat OpenShift Pipelines openshift-pipelines/pipelines-console-plugin-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-rhel9
    affected: workaround, no fix available
  • Red Hat Ceph Storage 9 thrift
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9 Red Hat Openshift Data Foundation 4 odf4/odf-console-rhel9, odf4/ocs-client-console-rhel9, odf4/odf-multicluster-console-rhel9
    affected: workaround, no fix available
  • Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9
    under investigation
  • Red Hat Cluster Observability Operator 1.5 cluster-observability-operator/monitoring-console-plugin-rhel9 1790854525, cluster-observability-operator/monitoring-console-plugin-pf5-rhel9 1790854526, cluster-observability-operator/monitoring-console-plugin-pf6-rhel9 1790854528
    fixed: vendor fix RHSA-2026:74609
  • Red Hat Migration Toolkit for Virtualization 2.10 migration-toolkit-virtualization/mtv-console-plugin-rhel9 1791248996
    fixed: vendor fix RHSA-2026:83663
  • Red Hat Migration Toolkit for Virtualization 2.11 migration-toolkit-virtualization/mtv-console-plugin-rhel9 1791616415
    fixed: vendor fix RHSA-2026:83662
  • Red Hat OpenShift AI 3.4 rhoai/odh-feature-server-rhel9 1791863220
    fixed: vendor fix RHSA-2026:84734
show 6 more
  • Red Hat OpenShift Container Platform 4.14 openshift4/ose-monitoring-plugin-rhel8 1792894511
    fixed: vendor fix RHSA-2026:89839
  • Red Hat OpenShift Container Platform 4.16 openshift4/ose-monitoring-plugin-rhel9 1792881187
    fixed: vendor fix RHSA-2026:89715
  • Red Hat OpenShift Dev Spaces 3.30 devspaces/openvsx-rhel9 1789144269, devspaces/pluginregistry-rhel9 1788883179
    fixed: vendor fix RHSA-2026:68754
  • Red Hat OpenShift Dev Spaces 3.31 devspaces/code-rhel9 1792599388
    fixed: vendor fix RHSA-2026:90321
  • Red Hat Cluster Observability Operator 1.5 cluster-observability-operator/perses-rhel9 1790854501, cluster-observability-operator/thanos-rhel9 1790854526, cluster-observability-operator/korrel8r-rhel9 1790854490, cluster-observability-operator/prometheus-rhel9 1790857922, cluster-observability-operator/alertmanager-rhel9 1790854499, cluster-observability-operator/perses-rhel9-operator 1790854601, +16 more Red Hat Migration Toolkit for Virtualization 2.10 migration-toolkit-virtualization/mtv-api-rhel9 1791228191, migration-toolkit-virtualization/mtv-rhel9-operator 1791228160, migration-toolkit-virtualization/mtv-virt-v2v-rhel9 1791228348, migration-toolkit-virtualization/mtv-operator-bundle 1791281489, migration-toolkit-virtualization/mtv-ova-proxy-rhel9 1791228163, migration-toolkit-virtualization/mtv-controller-rhel9 1791228194, +7 more Red Hat Migration Toolkit for Virtualization 2.11 migration-toolkit-virtualization/mtv-api-rhel9 1791228807, migration-toolkit-virtualization/mtv-rhel9-operator 1791228757, migration-toolkit-virtualization/mtv-virt-v2v-rhel9 1791229014, migration-toolkit-virtualization/mtv-operator-bundle 1791616914, migration-toolkit-virtualization/mtv-ova-proxy-rhel9 1791228762, migration-toolkit-virtualization/mtv-controller-rhel9 1791228801, +7 more Red Hat Build of Podman Desktop rh-podman-desktop.git Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend-module-loki, rhdh/red-hat-developer-hub-backstage-plugin-scaffolder-backend-module-orchestrator Red Hat Hardened Images grafana12.4, grafana13.1, rust 1.96.1-1.hum1, libgit2 1.9.4-2.hum1
    +7 more products
    Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1791509689, rhoai/rhai-cli-rhel9 1791509689, rhoai/odh-automl-rhel9 1791535789, rhoai/odh-mlflow-rhel9 1791865967, rhoai/odh-autorag-rhel9 1791557539, rhoai/odh-trainer-rhel9 1791869783, +99 more Red Hat OpenShift Container Platform 4 openshift4/ose-networking-console-plugin-rhel9 Red Hat OpenShift Container Platform 4.14 openshift4/ose-cli 1792888757, openshift4/ose-pod 1792892941, openshift4/ose-tests 1792894673, openshift4/ose-console 1792894610, openshift4/ose-coredns 1792892001, openshift4/ose-deployer 1792890904, +189 more Red Hat OpenShift Container Platform 4.16 openshift4/ose-cli-rhel9 1792881772, openshift4/ose-pod-rhel9 1792881268, openshift4/ose-sdn-rhel9 1792891515, openshift4/ose-etcd-rhel9 1792884751, openshift4/ose-tests-rhel9 1792892635, openshift4/ose-tools-rhel9 1792881835, +182 more Red Hat OpenShift Container Platform 5 openshift5/ose-monitoring-plugin-rhel9, openshift5/ose-networking-console-plugin-rhel9 Red Hat OpenShift Dev Spaces 3.30 devspaces/code-rhel9 1789145741, devspaces/server-rhel9 1789163798, devspaces/traefik-rhel9 1788882066, devspaces/udi-base-rhel9 1788883444, devspaces/code-sshd-rhel9 1789144422, devspaces/dashboard-rhel9 1789162884, +7 more Red Hat OpenShift Dev Spaces 3.31 devspaces/udi-rhel9 1792708612, devspaces/server-rhel9 1792775639, devspaces/openvsx-rhel9 1792494821, devspaces/traefik-rhel9 1792464177, devspaces/udi-base-rhel9 1792686842, devspaces/code-sshd-rhel9 1792598059, +9 more
    not affected: vulnerable code not present
  • Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-console-plugin-rhel9
    not affected: component 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

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/markdown-it/linkify-it/security/advisories/GHSA-v245-v573-v5vm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 linkify-it
<5.0.2
5.0.2

Affected products

  • markdown-it linkify-it

Classification

Weakness
  • CWE-407 Inefficient Algorithmic 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 markdown-it/linkify-it published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.