undici WebSocket client vulnerable to denial of service via fragment count bypass

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-12151
StatePUBLISHED
Assigneropenjs
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-17 17:16:42 UTC
Updated2026-07-13 13:16:27 UTC
DescriptionImpact: The undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service. Affected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint. All releases starting at undici 6.17.0 are affected. Patches: Upgrade to undici >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds: No workaround is available. The fix must be applied through an upgrade.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.004260000 probability, percentile 0.340160000 (date 2026-06-24)

Problem Types: CWE-400 | CWE-770 | CWE-400 CWE-400: Uncontrolled Resource Consumption | CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling | CWE-770 Allocation of Resources Without Limits or Throttling

VersionSourceTypeScoreSeverityVector
3.1ADPCVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1ce714d77-add3-4f53-aff5-83d477b104bbSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.10b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Nodejs Undici All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Undici Undici affected 6.26.0 semver Not specified
CNA Undici Undici unaffected 6.26.0 semver Not specified
CNA Undici Undici affected 7.0.0 7.28.0 semver Not specified
CNA Undici Undici unaffected 7.28.0 semver Not specified
CNA Undici Undici affected 8.0.0 8.5.0 semver Not specified
CNA Undici Undici unaffected 8.5.0 semver Not specified
ADP Red Hat Red Hat Enterprise Linux AppStream V. 10 Not specified Not specified
ADP Red Hat Red Hat Enterprise Linux AppStream V. 9 Not specified Not specified
ADP Red Hat Cluster Observability Operator 1.5.0 Not specified Not specified
ADP Red Hat Red Hat Developer Hub 1.10 Not specified Not specified
ADP Red Hat Red Hat Hardened Images Not specified Not specified
ADP Red Hat Red Hat OpenShift Dev Spaces 3.29 Not specified Not specified
ADP Red Hat Cryostat 4 Not specified Not specified
ADP Red Hat OpenShift Pipelines Not specified Not specified
ADP Red Hat Red Hat AMQ Broker 7 Not specified Not specified
ADP Red Hat Red Hat Build Of Podman Desktop Not specified Not specified
ADP Red Hat Red Hat Enterprise Linux 8 Not specified Not specified
ADP Red Hat Red Hat OpenShift AI RHOAI Not specified Not specified
ADP Red Hat Red Hat OpenShift Container Platform 4 Not specified Not specified
ADP Red Hat Red Hat Openshift Data Foundation 4 Not specified Not specified
ADP Red Hat Red Hat OpenShift Dev Spaces Not specified Not specified
ADP Red Hat Self-service Automation Portal 2 Not specified Not specified

References

ReferenceSourceLinkTags
cna.openjsf.org/security-advisories.html ce714d77-add3-4f53-aff5-83d477b104bb cna.openjsf.org Vendor Advisory
github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q ce714d77-add3-4f53-aff5-83d477b104bb github.com Vendor Advisory
access.redhat.com/security/cve/CVE-2026-12151 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:35891 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:35842 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:34342 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:36754 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:35892 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:35841 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:38236 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:36820 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:38009 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12151.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c security.access.redhat.com
bugzilla.redhat.com/show_bug.cgi 0b0ca135-0b70-47e7-9f44-1890c2a1c46c bugzilla.redhat.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: lpinca (en)

CNA: Nadav0077 (en)

CNA: UlisesGascon (en)

Additional Advisory Data

SourceTimeEvent
ADP2026-06-17T17:01:45.297ZReported to Red Hat.
ADP2026-06-17T16:05:38.785ZMade public.

Solutions

ADP: RHSA-2026:35842: Red Hat Enterprise Linux AppStream (v. 10)

ADP: RHSA-2026:35841: Red Hat Enterprise Linux AppStream (v. 10)

ADP: RHSA-2026:35892: Red Hat Enterprise Linux AppStream (v. 9)

ADP: RHSA-2026:35891: Red Hat Enterprise Linux AppStream (v. 9)

ADP: RHSA-2026:34342: Cluster Observability Operator 1.5.0

ADP: RHSA-2026:36754: Red Hat Developer Hub 1.10

ADP: RHSA-2026:38236: Red Hat Hardened Images

ADP: RHSA-2026:38009: Red Hat Hardened Images

ADP: RHSA-2026:36820: Red Hat OpenShift Dev Spaces 3.29

Workarounds

ADP: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

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