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Fencer Intel
high 7.5

CVE-2026-2229 json

undici is vulnerable to Unhandled Exception in undici WebSocket Client Due to Invalid server_max_window_bits Validation

published 7mo ago modified last mo. also GHSA-v9p9-hfj2-hcw8 , EUVD-2026-11704

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

ImpactThe undici WebSocket client is vulnerable to a denial-of-service attack due to improper validation of the server_max_window_bits parameter in the permessage-deflate extension. When a WebSocket client connects to a server, it automatically advertises support for permessage-deflate compression. A malicious server can respond with an out-of-range server_max_window_bits value (outside zlib's valid range of 8-15). When the server subsequently sends a compressed frame, the client attempts to create a zlib InflateRaw instance with the invalid windowBits value, causing a synchronous RangeError exception that is not caught, resulting in immediate process termination.

The vulnerability exists because:

* The isValidClientWindowBits() function only validates that the value contains ASCII digits, not that it falls within the valid range 8-15 * The createInflateRaw() call is not wrapped in a try-catch block * The resulting exception propagates up through the call stack and crashes the Node.js process

Patch / fix

  • npm undici 6.24.0, 7.24.0
  • undici undici 6.24.0: 7.24.0
  • Red Hat Cryostat 4 on RHEL 9 4.2.0-9
  • Red Hat Red Hat Enterprise Linux 10 1:22.22.2-1.el10_1, 1:24.14.1-2.el10_1
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 1:22.22.2-2.el10_0
  • Red Hat Red Hat Enterprise Linux 8 8100020260331102257.6d880403, 8100020260408131901.6d880403
  • Red Hat Red Hat Enterprise Linux 9 9070020260401095228.rhel9, 9070020260402152654.rhel9
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 9060020260409121057.rhel9
  • Red Hat Cluster Observability Operator 1.5.0 1782839279, 1782839996, 1782840539
  • Red Hat Red Hat Developer Hub 1.8 1776784286
  • Red Hat Red Hat Developer Hub 1.9 1777903262
  • Red Hat Red Hat OpenShift AI 2.16 1774282136
  • Red Hat Red Hat Openshift Data Foundation 4.18 1786705347, 1786705558, 1786705646, 1786705741, 1786705777, 1786705802, 1786705938, 1786706101, 1786706125, 1786706138, 1786706177, 1786706188, 1786706357, 1786706577, 1786706612, 1786706644, 1786706659, 1786706679, 1786706880
  • Red Hat Red Hat OpenShift Dev Spaces 3.28 1779814592
  • Red Hat Red Hat OpenShift Pipelines 1.2 1779910201
  • node-undici Debian 14 7.24.5+dfsg+~cs3.2.0-1

debian advisories DEBIAN-CVE-2026-2229

  • nodejs24 RHEL 10.1 1:24.14.1-2.el10_1
  • nodejs24-npm RHEL 10.1 1:11.11.0-1.24.14.1.2.el10_1
  • nodejs24-libs RHEL 10.1 1:24.14.1-2.el10_1
  • nodejs24-full-i18n RHEL 10.1 1:24.14.1-2.el10_1
  • npm RHEL 8 1:11.11.0-1.24.14.1.2.module+el8.10.0+24190+49a46c75
  • nodejs RHEL 8 1:24.14.1-2.module+el8.10.0+24190+49a46c75
  • nodejs-libs RHEL 8 1:24.14.1-2.module+el8.10.0+24190+49a46c75
  • nodejs-nodemon RHEL 8 3.0.3-1.module+el8.10.0+24190+49a46c75

red hat advisories RHSA-2026:7983RHSA-2026:7675RHSA-2026:7670RHSA-2026:7350RHSA-2026:7310RHSA-2026:7302

  • npm AlmaLinux 8 1:11.11.0-1.24.14.1.2.module_el8.10.0+4160+4819ac42
  • nodejs AlmaLinux 8 1:24.14.1-2.module_el8.10.0+4160+4819ac42
  • nodejs-libs AlmaLinux 8 1:24.14.1-2.module_el8.10.0+4160+4819ac42
  • nodejs-nodemon AlmaLinux 8 3.0.3-1.module_el8.10.0+4061+f8ceeab9
  • nodejs-full-i18n AlmaLinux 8 1:24.14.1-2.module_el8.10.0+4160+4819ac42
  • nodejs-packaging AlmaLinux 8 2021.06-6.module_el8.10.0+4086+70facd4a
  • nodejs-packaging-bundler AlmaLinux 8 2021.06-6.module_el8.10.0+4086+70facd4a
  • nodejs24-npm AlmaLinux 10 1:11.11.0-1.24.14.1.2.el10_1

almalinux advisories ALSA-2026:7670ALSA-2026:7675ALSA-2026:7350ALSA-2026:7123

  • nodejs24 Rocky Linux 10 1:24.14.1-2.el10_1
  • nodejs-nodemon Rocky Linux 8 3.0.3-1.module+el8.10.0+2084+ab509703
  • nodejs-packaging Rocky Linux 8 2021.06-6.module+el8.10.0+40048+6d99f608
  • nodejs22 Rocky Linux 10 1:22.22.2-1.el10_1
  • nodejs-nodemon Rocky Linux 9 3.0.3-3.module+el9.7.0+40025+0e0cf6b2
  • nodejs-packaging Rocky Linux 9 2021.06-6.module+el9.7.0+40052+e32ea525
  • nodejs-nodemon Rocky Linux 9 3.0.1-1.module+el9.7.0+40017+f0db1785
  • nodejs-nodemon Rocky Linux 9 3.0.1-1.module+el9.7.0+40018+a011993d

rocky linux advisories RLSA-2026:7675RLSA-2026:7670RLSA-2026:7080RLSA-2026:7350RLSA-2026:7302RLSA-2026:7123

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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-2026-2229 updated cvss 7.5

undici: Undici: Denial of Service via invalid WebSocket permessage-deflate extension parameter

  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-console-plugin-rhel9, openshift-lightspeed/lightspeed-console-plugin-pf5-rhel9 Red Hat OpenShift Pipelines openshift-pipelines/pipelines-console-plugin-rhel8
    affected: workaround, no fix available
  • Red Hat Developer Hub 1 rhdh/backstage-community-plugin-catalog-backend-module-scaffolder-relation-processor
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal
    affected: workaround, no fix available
  • Red Hat Cluster Observability Operator 1.5 cluster-observability-operator/logging-console-plugin-pf4-rhel9 1782839279, cluster-observability-operator/logging-console-plugin-pf5-rhel9 1782840539, cluster-observability-operator/troubleshooting-panel-console-plugin-pf6-rhel9 1782839996
    fixed: vendor fix RHSA-2026:34342
  • Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-rhel9 4.2.0-9, cryostat/cryostat-openshift-console-plugin-rhel9 4.2.0-9
    fixed: vendor fix RHSA-2026:17789
  • Red Hat Developer Hub 1.8 rhdh 1776784286
    fixed: vendor fix RHSA-2026:9742
  • Red Hat Developer Hub 1.9 rhdh 1777903262
    fixed: vendor fix RHSA-2026:13826
  • Red Hat Enterprise Linux AppStream (v. 8) nodejs 22.22.2-1.module+el8.10.0+24148+847b6786, nodejs 24.14.1-2.module+el8.10.0+24190+49a46c75, nodejs-libs 22.22.2-1.module+el8.10.0+24148+847b6786, nodejs-libs 24.14.1-2.module+el8.10.0+24190+49a46c75, nodejs-nodemon 3.0.1-1.module+el8.10.0+24148+847b6786, nodejs-nodemon 3.0.3-1.module+el8.10.0+24190+49a46c75, +8 more
    fixed: vendor fix RHSA-2026:7123
show 14 more
  • Red Hat Enterprise Linux AppStream (v. 9) nodejs 22.22.2-1.module+el9.7.0+24157+8ddb2461, nodejs 24.14.1-2.module+el9.7.0+24166+51c9666b, nodejs-libs 22.22.2-1.module+el9.7.0+24157+8ddb2461, nodejs-libs 24.14.1-2.module+el9.7.0+24166+51c9666b, nodejs-nodemon 3.0.1-1.module+el9.7.0+24157+8ddb2461, nodejs-nodemon 3.0.3-3.module+el9.7.0+24166+51c9666b, +8 more
    fixed: vendor fix RHSA-2026:7302
  • Red Hat Enterprise Linux AppStream (v. 10) nodejs 22.22.2-1.el10_1, nodejs22 22.22.2-1.el10_1, nodejs24 24.14.1-2.el10_1, nodejs-libs 22.22.2-1.el10_1, nodejs24-libs 24.14.1-2.el10_1, nodejs-full-i18n 22.22.2-1.el10_1, +3 more
    fixed: vendor fix RHSA-2026:7080
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) nodejs 22.22.2-2.el10_0, nodejs22 22.22.2-2.el10_0, nodejs-libs 22.22.2-2.el10_0, nodejs-full-i18n 22.22.2-2.el10_0, nodejs-npm 10.9.7-1.22.22.2.2.el10_0
    fixed: vendor fix RHSA-2026:7310
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) nodejs 22.22.2-1.module+el9.6.0+24196+39669d4e, nodejs-libs 22.22.2-1.module+el9.6.0+24196+39669d4e, nodejs-nodemon 3.0.1-1.module+el9.6.0+23473+45664c2d, npm 10.9.7-1.22.22.2.1.module+el9.6.0+24196+39669d4e, nodejs-full-i18n 22.22.2-1.module+el9.6.0+24196+39669d4e, nodejs-packaging 2021.06-4.module+el9.6.0+23473+45664c2d, +1 more
    fixed: vendor fix RHSA-2026:7983
  • Red Hat OpenShift AI 2.16 rhoai 1774282136
    fixed: vendor fix RHSA-2026:5807
  • Red Hat OpenShift AI 3.3 rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9 1790013905
    fixed: vendor fix RHSA-2026:73987
  • 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 OpenShift Dev Spaces 3.28 devspaces/code-rhel9 1779814592
    fixed: vendor fix RHSA-2026:21772
  • Red Hat OpenShift Pipelines 1.20 openshift-pipelines/pipelines-console-plugin-rhel9 1779910201
    fixed: vendor fix RHSA-2026:21931
  • Red Hat Cluster Observability Operator 1.5 cluster-observability-operator/perses-rhel9 1782839109, cluster-observability-operator/thanos-rhel9 1782840280, cluster-observability-operator/korrel8r-rhel9 1782839157, cluster-observability-operator/prometheus-rhel9 1782840780, cluster-observability-operator/alertmanager-rhel9 1782840761, cluster-observability-operator/perses-rhel9-operator 1782839191, +16 more Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-db-rhel9 4.2.0-13, cryostat/jfr-datasource-rhel9 4.2.0-9, cryostat/cryostat-reports-rhel9 4.2.0-9, cryostat/cryostat-storage-rhel9 4.2.0-13, cryostat/cryostat-operator-bundle 4.2.0-7, cryostat/cryostat-rhel9-operator 4.2.0-13, +2 more Red Hat Developer Hub 1.8 rhdh 1776783947, rhdh 1776787729 Red Hat Developer Hub 1.9 rhdh 1777902709, rhdh 1777909942 Red Hat JBoss Enterprise Application Platform 8 org.keycloak-keycloak-parent Red Hat JBoss Enterprise Application Platform Expansion Pack org.keycloak-keycloak-parent
    not affected: vulnerable code not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-pipeline-runtime-minimal-cpu-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9, rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9, rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9, rhoai/odh-workbench-jupyter-minimal-rocm-py312-rhel9, +11 more
    not affected: component not present
  • Red Hat OpenShift AI 2.16 rhoai 1774282058, rhoai 1774282073, rhoai 1774282078, rhoai 1774282087, rhoai 1774282092, rhoai 1774282093, +19 more Red Hat OpenShift AI 3.3 rhoai/odh-cli-rhel9 1790070206, rhoai/rhai-cli-rhel9 1790070206, rhoai/odh-mlflow-rhel9 1789653606, rhoai/odh-trainer-rhel9 1790136369, rhoai/odh-maas-api-rhel9 1790131842, rhoai/odh-mlserver-rhel9 1789121365, +76 more 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 OpenShift Dev Spaces devspaces/openvsx-rhel9, devspaces/code-sshd-rhel9
    not affected: component not present
  • Red Hat OpenShift Dev Spaces 3.28 devspaces/udi-rhel9 1779829736, devspaces/server-rhel9 1779342423, devspaces/openvsx-rhel9 1779528224, devspaces/traefik-rhel9 1779786779, devspaces/udi-base-rhel9 1779741066, devspaces/code-sshd-rhel9 1779813519, +9 more Red Hat OpenShift Pipelines 1.20 openshift-pipelines/pipelines-nop-rhel9 1779824303, openshift-pipelines/pipelines-opc-rhel9 1779509912, openshift-pipelines/pipelines-cache-rhel9 1779781652, openshift-pipelines/pipelines-events-rhel9 1779824120, openshift-pipelines/pipelines-hub-ui-rhel9 1779912885, openshift-pipelines/pipelines-cli-tkn-rhel9 1779257473, +28 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
yes
Technical impact
partial
Assessed
7mo ago

Exploit prediction

1.00% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-09).

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
CISA ADP 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 undici
<6.24.0
>=7.0.0, <7.24.0
6.24.0
7.24.0

Affected products

  • undici undici
  • Red Hat Cryostat 4 on RHEL 9
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
  • Red Hat Cluster Observability Operator 1.5.0
  • Red Hat Red Hat Developer Hub 1.8
  • Red Hat Red Hat Developer Hub 1.9
  • Red Hat Red Hat OpenShift AI 2.16
  • Red Hat Red Hat Openshift Data Foundation 4.18
  • Red Hat Red Hat OpenShift Dev Spaces 3.28
  • Red Hat Red Hat OpenShift Pipelines 1.2
  • Red Hat OpenShift Lightspeed
  • Red Hat OpenShift Pipelines
  • Red Hat Red Hat Developer Hub
  • Red Hat Red Hat JBoss Enterprise Application Platform 8
  • Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack
  • Red Hat Red Hat OpenShift AI (RHOAI)
  • Red Hat Red Hat OpenShift Dev Spaces
  • Red Hat Self-service automation portal 2

Classification

Weakness
  • CWE-248 Uncaught Exception
  • CWE-1284 Improper Validation of Specified Quantity in Input

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.