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No exploitation reportedFix available

CVE-2026-2229

No exploitation reported by the sources we read.

  • Published2026-03-12
  • Fixed in7.24.0 · 6.24.0
  • WeaknessCWE-1284 · CWE-248

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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

Timeline

dates in UTC
  1. 2026-03-1221:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-2229?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-2229?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Nodejs undici
BranchAffectedFixed in
7.x≥ 7.0.0, < 7.24.07.24.0
6.24< 6.24.06.24.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • nodejsAlmaLinux:9all versions · fixed in 1:24.14.1-2.module_el9.7.0+222+ef1c61e1and 4 other packages
  • nodejsAlmaLinux:8all versions · fixed in 1:22.22.2-1.module_el8.10.0+4158+e796f37fand 4 other packages
  • nodejsAlmaLinux:8all versions · fixed in 1:24.14.1-2.module_el8.10.0+4160+4819ac42and 4 other packages
  • nodejs-docsAlmaLinux:10all versions · fixed in 1:22.22.2-1.el10_1
  • nodejs-nodemonAlmaLinux:9all versions · fixed in 3.0.3-3.module_el9.7.0+209+ecf6523e
  • nodejs-nodemonAlmaLinux:8all versions · fixed in 3.0.1-1.module_el8.10.0+4006+3c416519
  • nodejs-nodemonAlmaLinux:8all versions · fixed in 3.0.3-1.module_el8.10.0+4061+f8ceeab9
  • nodejs-packagingAlmaLinux:9all versions · fixed in 2021.06-6.module_el9.7.0+209+ecf6523e

11 more package ranges on OSV.dev

Vendor advisories

  • RHSA-2026:56431 Red Hat Product Security68 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.18.27 security, enhancement & bug fix update

  • RHSA-2026:34342 Red Hat Product Security12 products fixed

    Red Hat Security Advisory: Cluster Observability Operator 1.5.0

  • RHSA-2026:21772 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.28.0 Release.

  • RHSA-2026:17789 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat build of Cryostat 4.2.0: new RHEL 9 container image security update

  • RHSA-2026:13826 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Developer Hub 1.9.4 release.

  • RHSA-2026:9742 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Developer Hub 1.8.6 release.

9 more advisories

Full record on NVD

Fix

  1. Update Nodejs undici to 7.24.0 · 6.24.0
  2. Vendor fix Red Hat Product Security RHSA-2026:56431 · 68 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.18/html/updating_openshift_data_foundation/updating-ocs-…
  3. Vendor fix Red Hat Product Security RHSA-2026:34342 · 12 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2026:21772 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  5. Vendor fix Red Hat Product Security RHSA-2026:17789 · 4 productsYou can download the Cryostat 4 on RHEL 9 container images that this update provides from the Red Hat Container Registry at registry.access.redhat.com. Installation instructions for your platform are available in the Red Hat Container Catalog (see the References section). Dockerfiles and scripts s…
  6. Vendor fix Red Hat Product Security RHSA-2026:13826 · 1 productFor more about Red Hat Developer Hub, see References links
  7. Vendor fix Red Hat Product Security RHSA-2026:7983 · 43 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionnone2026-03-13
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-1284, CWE-248read 2026-10-23
  • FIRST EPSSEPSS score0.9 %2026-10-22
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-03-12
Last Modified
2026-09-04
NVD status
Modified

Frequently asked questions

What is CVE-2026-2229?

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

Is CVE-2026-2229 actively exploited?

Active exploitation of CVE-2026-2229 has not been confirmed. Its EPSS score was 0.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-2229?

CVE-2026-2229 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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