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Fencer Vulns
low 3.7

CVE-2026-84947 json

undici vulnerable to response truncation via oversized chunked responses in the dump interceptor

published 2026-09-04 2 mo ago modified 2026-09-29 40 d ago also EUVD-2026-71517 , GHSA-2gqq-gqf2-x968

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

undici's dump interceptor reads and discards a response body up to a configurable maximum size. When a response declares a Content-Length that exceeds the maximum, the interceptor aborts cleanly, but when a response has no Content-Length and is chunked, the interceptor instead signals completion early once the accumulated size reaches the maximum, without pausing or aborting the request. Because the underlying parser keeps delivering body bytes, a second completion signal fires and trips an internal assertion, which aborts the request and tears down the connection. The application is left observing a misleading successful status with an empty or truncated body while the connection has actually been disconnected. This affects undici versions from 7.1.0 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-2026-84947

  • 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

  • pi-coding-agent openSUSE Leap 16.0 1.0.4-bp160.1.1
  • pi-coding-agent openSUSE Tumbleweed 0.87.1-1.1

opensuse advisories openSUSE-SU-2026:22111-1openSUSE-SU-2026:11884-1

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-2026-84947 updated cvss 6.5

undici: Undici: Response truncation and connection termination

  • Red Hat Exploit Intelligence exploit-intelligence/vulnerability-analysis-rhel9
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Pipelines openshift-pipelines/pipelines-console-plugin-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-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 Build of Podman Desktop rh-podman-desktop.git 1.1.0, rh-podman-desktop a4ea1f988eb28bc86ab3516bba3a4973b252a17e 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 8 npm, nodejs, nodejs-libs, nodejs-nodemon, ubi8/nodejs-24, rhel8/nodejs-24, +5 more
    +2 more products
    Red Hat Enterprise Linux 9 npm, nodejs, nodejs-libs, ubi9/nodejs-24, rhel9/nodejs-24, nodejs-full-i18n, +2 more Red Hat Enterprise Linux 10 ubi10/nodejs-24, rhel10/nodejs-24, grafana 12.4.3-2.el10, nodejs26 26.1.0-1.el10, ubi10/nodejs-24-minimal, rhel10/nodejs-24-minimal, +2 more
    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-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 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/openvsx-rhel9, devspaces/dashboard-rhel9, devspaces/pluginregistry-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Trusted Artifact Signer rhtas/rhtas-console-ui-rhel9 Red Hat Secrets Management Console for Red Hat OpenShift external-secrets-management/console-plugin-rhel9
    affected: workaround, 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: 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 Hardened Images rust 1.97.1-2.hum1, jaeger 2.20.0-0.8.hum1, prometheus3.13 3.13.2-0.2.hum1
    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

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm undici
>=7.1.0, <7.29.1
>=8.0.0, <8.10.2
7.29.1
8.10.2

Affected products

  • undici undici

Classification

Weakness

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.