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Fencer Vulns
low 3.7

CVE-2026-6733 json

undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse

published 2026-06-17 4 mo ago modified 2026-09-10 1 mo ago also GHSA-35p6-xmwp-9g52 , EUVD-2026-37769

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 12%
public exploits
0
none known

Summary

Impact: Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.

This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.

Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0.

Workarounds: Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.

Patch / fix

  • npm undici 6.27.0, 7.28.0, 8.5.0
  • undici undici 6.26.0, 7.28.0, 8.5.0
  • node-undici Debian 14 8.5.0+dfsg+~cs3.2.0-1

debian advisories DEBIAN-CVE-2026-6733

  • npm RHEL 8 1:10.9.8-1.22.23.1.1.module+el8.10.0+24500+8eb51621
  • nodejs RHEL 8 1:22.23.1-1.module+el8.10.0+24500+8eb51621
  • nodejs-libs RHEL 8 1:22.23.1-1.module+el8.10.0+24500+8eb51621
  • nodejs-nodemon RHEL 8 3.0.1-1.module+el8.10.0+24500+8eb51621
  • nodejs-full-i18n RHEL 8 1:22.23.1-1.module+el8.10.0+24500+8eb51621
  • nodejs-packaging RHEL 8 2021.06-6.module+el8.10.0+24500+8eb51621
  • nodejs-packaging-bundler RHEL 8 2021.06-6.module+el8.10.0+24500+8eb51621
  • npm RHEL 8 1:11.16.0-1.24.18.0.1.module+el8.10.0+24481+7a71fac8

red hat advisories RHSA-2026:41947RHSA-2026:39868RHSA-2026:38236RHSA-2026:38009RHSA-2026:35891RHSA-2026:35892

  • nodejs16 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 16.20.2-150400.3.42.1
  • nodejs18 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 18.20.8-150400.9.39.1
  • nodejs20 SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 20.20.2-150500.11.30.1
  • nodejs24 SLES for SAP applications 16.0, SLES 16.0 24.18.0-160000.1.1
  • nodejs22 SLE Module for Web and Scripting 15 SP7 22.23.0-150700.3.12.1
  • nodejs24 SLE Module for Web and Scripting 15 SP7 24.17.0-150700.15.11.1
  • nodejs22 SLES for SAP applications 16.0, SLES 16.0 22.23.0-160000.1.1
  • nodejs18 SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 18.20.8-8.44.1

suse advisories SUSE-SU-2026:4355-1SUSE-SU-2026:4261-1SUSE-SU-2026:4248-1SUSE-SU-2026:3930-1SUSE-SU-2026:3929-1SUSE-SU-2026:22565-1

  • nodejs24 openSUSE Leap 16.0 24.18.0-160000.1.1
  • nodejs22 openSUSE Leap 16.0 22.23.0-160000.1.1
  • nodejs24 openSUSE Tumbleweed 24.17.0-1.1

opensuse advisories openSUSE-SU-2026:21236-1openSUSE-SU-2026:21058-1openSUSE-SU-2026:11121-1

  • npm AlmaLinux 8 1:10.9.8-1.22.23.1.1.module_el8.10.0+4231+1bf2f855
  • nodejs AlmaLinux 8 1:22.23.1-1.module_el8.10.0+4231+1bf2f855
  • nodejs-libs AlmaLinux 8 1:22.23.1-1.module_el8.10.0+4231+1bf2f855
  • nodejs-nodemon AlmaLinux 8 3.0.1-1.module_el8.10.0+3956+47c9ee9f
  • nodejs-full-i18n AlmaLinux 8 1:22.23.1-1.module_el8.10.0+4231+1bf2f855
  • nodejs-packaging AlmaLinux 8 2021.06-6.module_el8.10.0+4158+e796f37f
  • nodejs-packaging-bundler AlmaLinux 8 2021.06-6.module_el8.10.0+4158+e796f37f
  • npm AlmaLinux 8 1:11.16.0-1.24.18.0.1.module_el8.10.0+4228+2938bc94

almalinux advisories ALSA-2026:41947ALSA-2026:39868ALSA-2026:35841ALSA-2026:35842ALSA-2026:35891ALSA-2026:35892

  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.9.0+1760+903d54b9
  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.10.0+1667+4a788d89
  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.10.0+1824+532140ee
  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.10.0+1823+b5789597
  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.10.0+1924+614dc87f
  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.10.0+1666+930e28e8
  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.10.0+1988+437f3d23
  • nodejs-nodemon Rocky Linux 8 3.0.1-1.module+el8.10.0+1989+e60144d9

rocky linux advisories RLSA-2026:41947RLSA-2026:39868RLSA-2026:35841RLSA-2026:35842RLSA-2026:35891RLSA-2026:35892

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-2026-6733 updated cvss 3.7

undici: Undici: Response queue poisoning on reused keep-alive sockets can lead to incorrect response delivery.

  • Red Hat Cryostat 4 undici, grafana-infinity-datasource-npm, cryostat-openshift-console-plugin-npm Red Hat OpenShift Pipelines openshift-pipelines/pipelines-console-plugin-rhel8, openshift-pipelines/pipelines-console-plugin-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-rhel9 Red Hat AMQ Broker 7 undici Red Hat Build of Podman Desktop rh-podman-desktop.git Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Enterprise Linux 8 npm, nodejs, nodejs-libs, nodejs-nodemon, nodejs-full-i18n, nodejs-packaging, +1 more
    +6 more products
    Red Hat Hardened Images nodejs25 Red Hat OpenShift AI (RHOAI) 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, rhoai/odh-mod-arch-autorag-rhel9, +3 more Red Hat OpenShift Container Platform 4 openshift4/ose-console-rhel9, openshift4/ose-monitoring-plugin-rhel9, openshift4/ose-agent-installer-ui-rhel9 Red Hat OpenShift Container Platform 5 openshift5/ose-console-rhel9, openshift5/ose-agent-installer-ui-rhel9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/openvsx-rhel9, devspaces/dashboard-rhel9, devspaces/pluginregistry-rhel9 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 Enterprise Linux AppStream (v. 8) nodejs 22.23.1-1.module+el8.10.0+24500+8eb51621, nodejs 24.18.0-1.module+el8.10.0+24481+7a71fac8, nodejs-libs 22.23.1-1.module+el8.10.0+24500+8eb51621, nodejs-libs 24.18.0-1.module+el8.10.0+24481+7a71fac8, nodejs-nodemon 3.0.1-1.module+el8.10.0+24500+8eb51621, nodejs-nodemon 3.0.3-1.module+el8.10.0+24190+49a46c75, +8 more
    fixed: vendor fix RHSA-2026:41947
  • Red Hat Enterprise Linux AppStream (v. 9) nodejs 22.23.1-1.module+el9.8.0+24457+996af7aa, nodejs 24.18.0-1.module+el9.8.0+24456+b244c3b4, nodejs-libs 22.23.1-1.module+el9.8.0+24457+996af7aa, nodejs-libs 24.18.0-1.module+el9.8.0+24456+b244c3b4, nodejs-nodemon 3.0.1-1.module+el9.8.0+24156+bb41d456, nodejs-nodemon 3.0.3-3.module+el9.8.0+24355+35d95b59, +8 more
    fixed: vendor fix RHSA-2026:35892
  • Red Hat Enterprise Linux AppStream (v. 10) nodejs 22.23.1-2.el10_2, nodejs22 22.23.1-2.el10_2, nodejs24 24.18.0-1.el10_2, nodejs-libs 22.23.1-2.el10_2, nodejs24-libs 24.18.0-1.el10_2, nodejs-full-i18n 22.23.1-2.el10_2, +3 more
    fixed: vendor fix RHSA-2026:35842
  • Red Hat Hardened Images nodejs26 26.5.0-1.3.hum1, nodejs24 24.18.0-0.3.hum1, nodejs26-bin 26.5.0-1.3.hum1, nodejs24-bin 24.18.0-0.3.hum1, nodejs26-libs 26.5.0-1.3.hum1, nodejs24-libs 24.18.0-0.3.hum1, +6 more
    fixed: vendor fix RHSA-2026:38236
  • Red Hat Openshift Data Foundation 4.18 odf4/cephcsi-rhel9 1786705347, odf4/odf-cli-rhel9 1786705938, odf4/mcg-core-rhel9 1786705558, odf4/odf-console-rhel9 1786706577, odf4/mcg-rhel9-operator 1786705646, odf4/ocs-rhel9-operator 1786705802, +13 more
    fixed: vendor fix RHSA-2026:56431
  • Red Hat Hardened Images rust Red Hat Openshift Data Foundation 4.18 odf4/mcg-operator-bundle 1786708633, odf4/ocs-operator-bundle 1786708778, odf4/odf-operator-bundle 1786709119, odf4/cephcsi-operator-bundle 1786708508, odf4/odr-hub-operator-bundle 1786709184, odf4/rook-ceph-operator-bundle 1786709254, +7 more
    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
4 mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% 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

Affected packages

ecosystem package affected fixed in
npm undici
<6.27.0
>=7.0.0, <7.28.0
>=8.0.0, <8.5.0
6.27.0
7.28.0
8.5.0

Affected products

  • undici undici

Classification

Weakness
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

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.