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Fencer Intel
medium 5.9

CVE-2026-87029 json

undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor

published 27d ago modified 15d ago also EUVD-2026-102347 , GHSA-55wc-3pg8-jfw6

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

undici is an HTTP client library for Node.js. In versions 7.15.0 through 7.30.0 and 8.0.0 through 8.12.1, its decompress interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw, and while undici's engine converts a synchronous throw from a downstream handler into a per-request failure, that protection is absent when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, such as the built-in dump interceptor which throws when a response exceeds its configured maximum size, escapes as an uncaught exception that terminates the Node.js process. A malicious or compromised HTTP server can crash any client that composes the decompress interceptor with such a handler by returning a small compressed body that decompresses to more than the configured limit, so only the decompressed size matters and the bytes on the wire stay tiny. The issue is fixed in undici 7.30.1 and 8.12.2, and users should upgrade to one of those versions or later. As a workaround, avoid composing the decompress interceptor with a response handler that throws during response processing until upgrading.

Patch / fix

  • npm undici 7.30.1, 8.12.2
  • undici undici 7.30.1, 8.12.2
  • node-undici Debian 14 8.12.2+dfsg+~cs3.2.3-1

debian advisories DEBIAN-CVE-2026-87029

  • nodejs24 hummingbird 1 24.21.0-1.5.hum1
  • nodejs24-bin hummingbird 1 24.21.0-1.5.hum1
  • nodejs24-npm hummingbird 1 11.19.0-1.24.21.0.1.5.hum1
  • nodejs24-libs hummingbird 1 24.21.0-1.5.hum1
  • nodejs24-npm-bin hummingbird 1 24.21.0-1.5.hum1
  • nodejs24-full-i18n hummingbird 1 24.21.0-1.5.hum1
  • nodejs26 hummingbird 1 26.11.1-0.4.hum1
  • nodejs26-bin hummingbird 1 26.11.1-0.4.hum1

red hat advisories RHSA-2026:84706RHSA-2026:84657

Is CVE-2026-87029 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-2026-87029 updated cvss 5.9

undici: undici: Denial of Service via unhandled exception in decompress interceptor

  • Red Hat Cryostat 4 cryostat/cryostat-openshift-console-plugin-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Exploit Intelligence exploit-intelligence/vulnerability-analysis-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat AMQ Broker 7 amq-broker-bin.zip 7.14.1.CR3, amq-broker-maven-repository.zip 7.14.1.CR3 Red Hat Ansible Automation Platform 2 automation-platform-ui 2.6.15-1.el9ap Red Hat Build of Podman Desktop rh-podman-desktop a4ea1f988eb28bc86ab3516bba3a4973b252a17e
    affected: no fix available “Fix deferred”
  • 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
    affected: no fix available
  • Red Hat Enterprise Linux 8 npm, nodejs, nodejs-libs, ubi8/s2i-base, nodejs-nodemon, ubi8/nodejs-24, +4 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, grafana 12.4.3-2.el10, nodejs26 26.1.0-1.el10, ubi10/nodejs-24-minimal, nodejs22 22.23.2-3.el10_2, nodejs24 24.21.0-1.el10_2
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images nodejs25 25.9.0-1.7.hum1
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, 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, +7 more Red Hat OpenShift Container Platform 4 wasmedge, wasmedge-rt, openshift4/ose-monitoring-plugin-rhel9 Red Hat OpenShift Container Platform 5 openshift5/ose-monitoring-plugin-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
    affected: no fix available “Fix deferred”
  • Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/openvsx-rhel9, devspaces/dashboard-rhel9, devspaces/pluginregistry-rhel9
    affected: no fix available
show 5 more
  • Red Hat Secrets Management Console for Red Hat OpenShift external-secrets-management/console-plugin-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images nodejs24 24.21.0-1.5.hum1, nodejs26 26.11.1-0.4.hum1, nodejs24-bin 24.21.0-1.5.hum1, nodejs26-bin 26.11.1-0.4.hum1, nodejs24-libs 24.21.0-1.5.hum1, nodejs26-libs 26.11.1-0.4.hum1, +6 more
    fixed: vendor fix RHSA-2026:84706
  • Red Hat Trusted Artifact Signer 1.5 rhtas/rhtas-console-ui-rhel9 1793114810
    fixed: vendor fix RHSA-2026:95124
  • Red Hat Hardened Images grafana12.4 12.4.12-0.4.hum1 Red Hat Trusted Artifact Signer 1.5 rhtas/rhtas-console-rhel9 1793108442
    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
26d ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% 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
NVD 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 undici
>=7.15.0, <7.30.1
>=8.0.0, <8.12.2
7.30.1
8.12.2

Affected products

  • undici undici

Classification

Weakness

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 nodejs/undici published their own advisory on GitHub. Reviewed sources take precedence over it.