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Fencer Vulns
medium 5.9

CVE-2026-18149 json

undici vulnerable to Denial of Service via orphaned RetryHandler response body

published 2026-09-04 2 mo ago modified 2026-09-29 40 d ago also EUVD-2026-71617 , GHSA-pmjh-fq2x-6v4x

cvss
5.9
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 41%
public exploits
0
none known

Summary

undici's retry handler can leave an already-exposed response body pending forever. When a server returns a successful response that declares a Content-Length, sends only part of the body, and closes the connection, the retry handler retries the request. If the retry returns a non-retryable status such as 400, the handler forwards that new response downstream and replaces its internal response stream, but the original response body that the application still holds is never ended or destroyed. As a result calls that read that body never settle, and the configured body timeout does not fire because its timer is tied to the connection parser rather than the orphaned body. An attacker-controlled server can trigger this with two short responses without keeping a connection open, and repeated requests accumulate pending promises and streams that can exhaust application concurrency or memory. This affects undici versions from 7.11.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.

Patch / fix

  • npm undici 7.29.1, 8.10.2
  • undici undici 7.29.1, 8.10.2
  • node-undici Debian 14 8.10.2+dfsg+~cs3.2.2-1

debian advisories DEBIAN-CVE-2026-18149

  • grafana12.4 hummingbird 1 12.4.10-0.2.hum1
  • nodejs24 hummingbird 1 24.18.1-0.2.2.hum1
  • nodejs24-bin hummingbird 1 24.18.1-0.2.2.hum1
  • nodejs24-npm hummingbird 1 11.16.0-1.24.18.1.0.2.2.hum1
  • nodejs24-libs hummingbird 1 24.18.1-0.2.2.hum1
  • nodejs24-npm-bin hummingbird 1 24.18.1-0.2.2.hum1
  • nodejs24-full-i18n hummingbird 1 24.18.1-0.2.2.hum1
  • nodejs26 hummingbird 1 26.7.0-1.5.2.hum1

red hat advisories RHSA-2026:66008RHSA-2026:54438RHSA-2026:54389

  • nodejs Azure Linux 3.0 24.21.0-1

azure linux advisories AZL-99942

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-18149 updated cvss 5.9

undici: undici: Denial of Service due to orphaned response body in retry handler

  • Red Hat OpenShift Pipelines openshift-pipelines/pipelines-console-plugin-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-rhel9 Red Hat Build of Podman Desktop rh-podman-desktop.git 1.1.0 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 Enterprise Linux 10 grafana 12.4.3-2.el10
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images nodejs25 25.9.0-1.6.hum1
    affected: workaround, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +6 more Red Hat OpenShift Container Platform 4 openshift4/ose-monitoring-plugin-rhel9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/openvsx-rhel9, devspaces/dashboard-rhel9, devspaces/pluginregistry-rhel9 Red Hat Trusted Artifact Signer rhtas/rhtas-console-ui-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images nodejs26 26.7.0-1.5.2.hum1, nodejs24 24.18.1-0.2.2.hum1, grafana12.4 12.4.10-0.2.hum1, nodejs26-bin 26.7.0-1.5.2.hum1, nodejs24-bin 24.18.1-0.2.2.hum1, nodejs26-libs 26.7.0-1.5.2.hum1, +7 more
    fixed: vendor fix RHSA-2026:66008
  • Red Hat Exploit Intelligence exploit-intelligence/vulnerability-analysis-rhel9 Red Hat AMQ Broker 7 amq-broker-bin.zip 7.14.1.CR2, amq-broker-maven-repository.zip 7.14.1.CR3 Red Hat Ansible Automation Platform 2 automation-platform-ui 2.6.13-1.el9ap Red Hat Enterprise Linux 8 npm, nodejs, nodejs-libs, nodejs-nodemon, ubi8/nodejs-24, nodejs-full-i18n, +3 more Red Hat Enterprise Linux 9 npm, nodejs, nodejs-libs, ubi9/nodejs-24, nodejs-full-i18n, ubi9/nodejs-24-minimal Red Hat Enterprise Linux 10 ubi10/nodejs-24, nodejs26 26.1.0-1.el10, ubi10/nodejs-24-minimal, nodejs22 22.23.2-1.el10_2, nodejs24 24.19.0-1.el10_2
    +6 more products
    Red Hat Hardened Images rust 1.97.1-2.hum1, jaeger 2.20.0-0.8.hum1, prometheus3.13 3.13.2-0.2.hum1 Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9 Red Hat OpenShift Container Platform 4 wasmedge, wasmedge-rt 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 Secrets Management Console for Red Hat OpenShift external-secrets-management/console-plugin-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 undici
>=7.11.0, <7.29.1
>=8.0.0, <8.10.2
7.29.1
8.10.2

Affected products

  • undici undici

Classification

Weakness
  • CWE-772 Missing Release of Resource after Effective Lifetime

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.

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